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pascal@23996
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1 ;***************************************************************
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pascal@23996
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2 ;****** This file is distributed under GPL
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pascal@23996
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3 ;***************************************************************
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pascal@23996
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4 ;VDPI init:
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pascal@23996
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5 ;Call char* prepare_vcpi(void *pagebuf) first to
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pascal@23996
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6 ;initialize paging tables needed for vm86.
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pascal@23996
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7 ;pagebuf needs to be 8k+4 bytes. Returns ptr to 1st unused byte.
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pascal@23996
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8 ;Then call int get_vcpi_interface(). Returns 1 if ok, 0 if bad.
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pascal@23996
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9 ;
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pascal@23996
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10 ;VCPI use:
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pascal@23996
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11 ;u32* malloc_vcpi(u32 size) - source in HIMEM.CPP
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pascal@23996
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12 ; Returns ptr to mallocated zero-terminated list of 4k page addrs
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pascal@23996
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13 ; Addresses are sorted in ascending order
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pascal@23996
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14 ; Never fails (will die if not enough mem)
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pascal@23996
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15 ;void read2vcpi(int fd, u32* vp, u32 size,
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pascal@23996
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16 ;void* xfer_buf, u16 xfer_size) - source in HIMEM.CPP
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pascal@23996
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17 ; Reads opened fd data into malloc_vcpi'ed memory
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pascal@23996
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18 ; Dies if file isn't exactly 'size' bytes long
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pascal@23996
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19 ; Needs intermediate buffer of exactly Nx4k bytes
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pascal@23996
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20 ;void memcpy_vcpi(u32 dstofs,u16 srcseg,u32 srcofs)
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pascal@23996
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21 ; copies 4k from conventional memory to VCPI
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pascal@23996
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22 ;void _vm2rm()
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pascal@23996
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23 ; switches you from vm86 to plain real mode
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pascal@23996
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24
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pascal@23996
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25
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pascal@23996
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26 ideal
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pascal@23996
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27 %PAGESIZE 1000
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pascal@23996
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28 %crefref
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pascal@23996
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29 %noincl
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pascal@23996
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30 %nomacs
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pascal@23996
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31 p386
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pascal@23996
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32
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pascal@23996
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33 ;****** Stuff for declaring descriptors
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pascal@23996
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34 struc descr
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pascal@23996
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35 limit dw ?
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pascal@23996
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36 base0 dw ?
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pascal@23996
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37 base16 db ?
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pascal@23996
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38 type db ?
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pascal@23996
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39 limit16 db ?
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pascal@23996
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40 base24 db ?
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pascal@23996
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41 ends descr
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pascal@23996
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42 macro descriptor name,typ,plevel,present,limit,gran,base
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pascal@23996
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43 ;;name descr <limit and 0ffffh,base and 0ffffh,low (base shr 16),typ or plevel or present,(limit shr 16) or gran,high (base shr 16)>
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pascal@23996
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44 name descr <limit and 0ffffh,base ,0 ,typ or plevel or present,(limit shr 16) or gran,0 >
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pascal@23996
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45 endm
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pascal@23996
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46 ; decriptor types (bit0..4 of descr.type )
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pascal@23996
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47 tss386_avail = 09h
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pascal@23996
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48 data_seg = 00010000b ; data segment
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pascal@23996
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49 expand_down = 00000100b ; =1 limit counts down from base
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pascal@23996
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50 writable = 00000010b ; =1 if write access allowed to data segment
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pascal@23996
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51 code_seg = 00011000b ; code segment
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pascal@23996
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52 conforming = 00000100b ; =1 code can be accesses and executed at any PL
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pascal@23996
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53 readable = 00000010b ; =1 if code also can be read (cannot be ovwritten)
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pascal@23996
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54 ; privilege levels (bit5..6 of descr.type )
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pascal@23996
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55 priv0 = 00000000b
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pascal@23996
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56 priv1 = 00100000b
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pascal@23996
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57 priv2 = 01000000b
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pascal@23996
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58 priv3 = 01100000b
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pascal@23996
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59 ; segment present bit (bit7 of descr.type )
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pascal@23996
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60 is_present = 10000000b
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pascal@23996
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61 not_present = 00000000b
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pascal@23996
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62 ;definition of granularity ( bits6..7 in descr.limit16 )
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pascal@23996
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63 gran_byte = 00000000b
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pascal@23996
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64 gran_page = 10000000b ; 4k granularity
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pascal@23996
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65 use_16 = 00000000b
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pascal@23996
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66 use_32 = 01000000b
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pascal@23996
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67
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pascal@23996
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68 ;****** rm32,imm16 helper
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pascal@23999
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69 macro movzx_e rm,i
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pascal@23999
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70 db 66h
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pascal@23999
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71 mov rm,i
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pascal@23999
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72 dw 0
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pascal@23996
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73 endm
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pascal@23996
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74
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pascal@23999
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75 macro pushd sreg
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pascal@23999
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76 db 66h
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pascal@23999
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77 push sreg
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pascal@23996
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78 endm
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pascal@23996
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79
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pascal@23996
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80 group DGROUP _TEXT
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pascal@23996
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81 assume cs:DGROUP,ds:DGROUP
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pascal@23996
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82
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pascal@23996
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83 segment _TEXT byte public use16 'CODE'
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pascal@23996
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84
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pascal@23996
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85 ;***************************************************************
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pascal@23996
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86 ;int get_vcpi_interface();
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pascal@23996
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87 ;****** Return: Z - page mapping for low 640k is 1:1
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pascal@23996
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88 ;****** NZ - otherwise (it's bad)
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pascal@23996
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89 ;****** Uses: Flags
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pascal@23996
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90 ;***************************************************************
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pascal@23996
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91 ;global _get_vcpi_interface:near
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pascal@23996
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92 proc _get_vcpi_interface near
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pascal@23996
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93
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pascal@23996
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94 ;push si di
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pascal@23996
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95
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pascal@23996
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96 ; Get and save VCPI pm interface
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pascal@23996
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97 ;mov si,offset gdt_vcpi ;DS:DI => 3 GDT entries for VCPI
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pascal@23996
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98 ;mov di,[si+page0_ofs-gdt_vcpi] ;ES:DI => page0
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pascal@23996
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99 ;push ds
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pascal@23996
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100 ;pop es
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pascal@23996
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101 ;push di
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pascal@23996
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102 ;mov ax,0DE01h ;get vcpi pm interface
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pascal@23996
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103 int 67h
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pascal@23996
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104 xchg [si+vcpi_pm_entry-gdt_vcpi],ebx ; bx=((640*1024) shr 12)
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pascal@23996
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105 ;xor bx,bx
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pascal@23996
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106
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pascal@23996
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107 ; Check that mapping for low 640k is 1:1
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pascal@23996
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108 pop si ; [page0_ofs]
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pascal@23996
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109 ;cld
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pascal@23996
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110 mov cx,bx
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pascal@23996
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111 @@map_chk:
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pascal@23996
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112 lodsd
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pascal@23996
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113 shr eax,12
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pascal@23996
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114 add al,cl
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pascal@23996
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115 cmp al,((640*1024) shr 12)
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pascal@23996
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116 loope @@map_chk
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pascal@23996
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117 ; Return
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pascal@23996
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118 @@bad:
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pascal@23996
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119 ret
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pascal@23996
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120 endp _get_vcpi_interface
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pascal@23996
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121
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pascal@23996
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122
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pascal@23996
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123 ;***************************************************************
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pascal@23996
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124 ;char* prepare_vcpi(void *pagebuf);
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pascal@23996
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125 ;****** Return: AX=>first unused byte in pagebuf
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pascal@23996
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126 ;****** Uses: Flags
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pascal@23996
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127 ;***************************************************************
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pascal@23996
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128 global prepare_vcpi:near
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pascal@23996
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129 proc prepare_vcpi near
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pascal@23996
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130
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pascal@23996
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131 ;Calculate pagedir/page0 addrs, initialize cr3 and pagedir[0]
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pascal@23996
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132 ; heap_top = prepare_vcpi(malloc_or_die(8*1024+4));
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pascal@23996
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133
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pascal@23996
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134 ;mov edx,cs
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pascal@23996
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135 ;shl edx,4 ;edx = linear addr of CS
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pascal@23996
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136 mov si,offset gdt_vcpi
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pascal@23996
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137 ; Fix up base of some gdt descriptors
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pascal@23996
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138 ; Note: 'add [dword xx.base0],edx' actually updates 24 bit quantity!
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pascal@23996
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139 ; Do NOT replace with mov!
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pascal@23996
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140 mov ebx,10000h-28h
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pascal@23996
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141 add [dword si+sw2pm_addr-gdt_vcpi],edx
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pascal@23996
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142 add [dword si+sw2pm_idtr_ptr-gdt_vcpi],edx
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pascal@23996
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143 @@fixup:
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pascal@23996
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144 add [dword bx+si+(gdt_code.base0)-gdt_vcpi+28h],edx
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pascal@23996
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145 add bx,8
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pascal@23996
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146 js @@fixup
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pascal@23996
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147 mov bh,10h
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pascal@23996
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148 extrn _heap_top:word
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pascal@23996
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149 movzx eax,[_heap_top]
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pascal@23996
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150 add eax,edx
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pascal@23996
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151 and ax,0f000h ;eax = 4k aligned linear addr of pagebuf
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pascal@23996
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152 add eax,ebx ;eax=page0 linear addr
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pascal@23996
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153 add [si+sw2pm_cr3-gdt_vcpi],eax
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pascal@23996
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154 mov edi,eax
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pascal@23996
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155 sub edi,edx
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pascal@23996
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156 mov al,3 ;add present+writable bits
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pascal@23996
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157 mov [bx+di],eax ;stuff it into pagedir[0]
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pascal@23996
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158 push ds
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pascal@23996
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159 pop es ;es:di->page0,es:di+1000h->pagedir
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pascal@23996
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160 ;page directory will use only one entry (4 bytes):
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pascal@23996
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161 ;cr3 => pagedir => page0 => ########
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pascal@23996
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162 ; (1 entry) (1024 => # 4M #
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pascal@23996
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163 ; entries)=> # page #
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pascal@23996
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164 ; => ########
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pascal@23996
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165 ; Return
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pascal@23996
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166 lea ax,[bx+di+4]
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pascal@23996
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167 mov [_heap_top],ax
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pascal@23996
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168 ;ret
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pascal@23996
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169 push di
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pascal@23996
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170 mov ax,0DE01h ;get vcpi pm interface
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pascal@23996
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171 jmp _get_vcpi_interface
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pascal@23996
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172
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pascal@23996
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173 endp prepare_vcpi
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pascal@23996
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174
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pascal@23996
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175 org $-40
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pascal@23996
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176 tss dd ?,? ;enough, we'll never use it anyway
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pascal@23996
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177 label gdt byte
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pascal@23996
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178 gdt_null descr <?> ;0000
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pascal@23996
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179 gdt_vcpi descr <?> ;0008
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pascal@23996
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180 gdt_vcpi2 descr <?> ;0010
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pascal@23996
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181 gdt_vcpi3 descr <?> ;0018
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pascal@23996
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182 org $-8
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pascal@23996
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183 global gdt_memcpy:descr
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pascal@23996
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184 gdt_memcpy descr <?>
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pascal@23996
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185 descriptor gdt_abs ,(data_seg+writable),priv0,is_present,0fffffh,(gran_page+use_32),0
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pascal@23996
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186 ;Note: code/data segs must be flagged use16 (i.e. use ip/sp, not eip/esp)
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pascal@23996
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187 ;Note: base addrs will be fixed up in prepare_vcpi()
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pascal@23996
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188 descriptor gdt_code,(code_seg+readable),priv0,is_present,0fffffh,(gran_page+use_16),0
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pascal@20751
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189 global gdt_data:descr
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pascal@23996
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190 descriptor gdt_data,(data_seg+writable),priv0,is_present,0fffffh,(gran_page+use_16),0
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pascal@23996
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191 descriptor gdt_tss ,tss386_avail ,priv0,is_present,0ffh ,gran_byte ,<offset tss>
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pascal@23996
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192 SEL_VCPI = (gdt_vcpi - gdt_null)
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pascal@23996
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193 SEL_TSS = (gdt_tss - gdt_null)
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pascal@23996
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194 SEL_ABS = (gdt_abs - gdt_null)
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pascal@23996
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195 SEL_CODE = (gdt_code - gdt_null)
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pascal@23996
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196 SEL_DATA = (gdt_data - gdt_null)
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pascal@23996
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197
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pascal@23996
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198 label gdtr pword
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pascal@23996
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199 gdt_lim dw 0ffffh
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pascal@23996
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200 gdt_base dw offset gdt,0
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pascal@23996
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201
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pascal@23996
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202 ;Note: layout dictated by vcpi api, don't rearrange!
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pascal@23996
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203 label sw2pm_params byte
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pascal@23996
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204 ;Note: base addrs will be fixed up in prepare_vcpi()
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pascal@23996
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205 label pagedir_laddr dword
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pascal@23996
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206 sw2pm_cr3 dd 1000h
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pascal@23996
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207 sw2pm_gdtr_ptr dw offset gdtr,0
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pascal@23996
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208 sw2pm_idtr_ptr dw offset idtr,0
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pascal@23996
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209 sw2pm_ldtr dw 0 ;we don't need it
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pascal@23996
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210 sw2pm_tr dw SEL_TSS ;vcpi thinks we need it... can't set to 0
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pascal@23996
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211 sw2pm_jumpaddr dd 0
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pascal@23996
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212 dw SEL_CODE
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pascal@23996
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213
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pascal@23996
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214 vcpi_pm_entry dd ((640*1024) shr 12)
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pascal@23996
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215 dw SEL_VCPI
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pascal@23996
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216
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pascal@23996
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217 label idtr pword
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pascal@23996
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218 idt_lim dw 03ffh ;we won't enable ints,
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pascal@23996
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219 idt_base dd 0 ; so let's leave it the same as for rm
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pascal@23996
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220
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pascal@23996
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221 ;***************************************************************
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pascal@23996
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222 switch_to_pm:
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pascal@23996
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223 assume cs:DGROUP,ds:DGROUP
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pascal@23996
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224 mov edx,esi
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pascal@23996
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225 movzx_e si,<offset sw2pm_params>
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pascal@23996
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226 org $-4
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pascal@23996
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227 sw2pm_addr dd ?
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pascal@23996
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228 pop [word sw2pm_jumpaddr] ; CS:EIP of protected mode entry-point
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pascal@23996
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229 ;mov [word sw2pm_jumpaddr+2],0
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pascal@23996
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230 ;mov [word sw2pm_jumpaddr+4],SEL_CODE
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pascal@23996
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231 mov ax,0DE0Ch ; vcpi: switch to pm
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pascal@23996
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232 cli ; load GDTR LDTR TR need 16 bytes in SS:ESP
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pascal@23996
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233 int 67h ; EAX, ESI, DS, ES, FS, GS destroyed
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pascal@23996
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234
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pascal@23996
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235
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pascal@23996
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236 ;***************************************************************
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pascal@23996
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237 ;void memcpy_vcpi(u32 dstofs,u16 srcseg,u32 srcofs);
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pascal@23996
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238 ;***************************************************************
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pascal@23996
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239 ;****** Copies PAGE_SIZE bytes
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pascal@23996
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240 ;****** Uses: Flags
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pascal@23996
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241 ;***************************************************************
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pascal@23996
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242 global vcpi_pm_copy_routine:near
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pascal@23996
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243 proc vcpi_pm_copy_routine near
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pascal@23996
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244
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pascal@23996
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245 struc pm_regs
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pascal@23996
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246 $$retaddr dw ?
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pascal@23996
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247 $$edi dd ?
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pascal@23996
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248 $$esi dd ?
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pascal@23996
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249 $$ebp dd ?
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pascal@23996
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250 $$esp dd ?
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pascal@23996
|
251 $$ebx dd ?
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pascal@23996
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252 $$edx dd ?
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pascal@23996
|
253 $$ecx dd ?
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pascal@23996
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254 $$eax dd ?
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pascal@23996
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255 ends
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pascal@23996
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256
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pascal@23996
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257 ;***************************************************************
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pascal@23996
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258 ;****** Helper: goes into 16bit pm and calls routine (addr on stk)
|
pascal@23996
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259 ;***************************************************************
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pascal@23996
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260 mov bp,sp ; ss:bp => struct pm_regs
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pascal@23996
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261
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pascal@23999
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262 mov bx,5 ; IRET stack for return to vm
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pascal@23999
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263 @@push_sreg:
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pascal@23999
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264 pushd ss ; fake pushd gs fs ds es ss
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pascal@23999
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265 dec bx
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pascal@23999
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266 jnz @@push_sreg ; (9 dwords)
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pascal@23996
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267 push ebp ; esp
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pascal@23996
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268 pushfd ; eflags: IF saved here
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pascal@23996
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269 pushd cs ;
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pascal@23999
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270 push bx ;\eip
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pascal@23999
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271 push offset vcpi_ret ;/
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pascal@23996
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272
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pascal@23996
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273 call switch_to_pm ; EAX, EDX/ESI, DS, ES, FS, GS destroyed
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pascal@23996
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274 assume nothing
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pascal@23996
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275 assume cs:DGROUP
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pascal@23996
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276
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pascal@23996
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277 ; Now we are in 16-bit protected mode
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pascal@23999
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278 mov bl,SEL_DATA
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pascal@23999
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279 mov ss,bx
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pascal@23999
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280 lea sp,[bp-8-9*4]
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pascal@23996
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281
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pascal@23996
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282 ; Call the routine (bp points to params on stack if any)
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pascal@23999
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283 call do_memcpy_vcpi ; set ds=all_addrspace
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pascal@23996
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284
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pascal@23996
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285 ; Ok, let's return to vm
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pascal@23996
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286 mov ax,0DE0Ch ; maybe we need whole eax?
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pascal@23996
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287 cli ; to be safe
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pascal@23996
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288 clts ;
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pascal@23999
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289 ; Go to vm86 mode. Sregs, esp, eflags (IF) restored from IRET stack
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pascal@23999
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290 jmp [pword cs:vcpi_pm_entry]
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pascal@23996
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291
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pascal@23996
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292 ;***************************************************************
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pascal@23996
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293
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pascal@23996
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294 ;***************************************************************
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pascal@23996
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295 ;****** Helper: This is where real copy is done
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pascal@23996
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296 ;***************************************************************
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pascal@23996
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297 label do_memcpy_vcpi near
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pascal@23996
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298
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pascal@23996
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299 push SEL_ABS
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pascal@23996
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300 pop ds
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pascal@23996
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301 push ds
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pascal@23996
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302 pop es
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pascal@23996
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303 assume nothing
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pascal@23996
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304 assume cs:DGROUP
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pascal@23996
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305
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pascal@23996
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306 ; Set up target addr:
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pascal@23996
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307 ; replace page mapping for page at 0 so
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pascal@23996
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308 ; that it points to dstofs
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pascal@23996
|
309 xchg eax,edi
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pascal@23996
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310 mov al,03h ; writeable, present
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pascal@23996
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311 call @@set_mapping
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pascal@23996
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312 xor edi,edi ;es:edi => remapped page
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pascal@23996
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313
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pascal@23996
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314 ; Set up source addr
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pascal@23996
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315 mov esi,edx
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pascal@23996
|
316
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pascal@23996
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317 ; Do copying
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pascal@23996
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318 db 67h ;address width override for esi/edi
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pascal@23996
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319 rep movsb
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pascal@23996
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320
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pascal@23996
|
321 @@set_mapping:
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pascal@23996
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322 mov esi,[cs:sw2pm_cr3]
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pascal@23996
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323 xchg [esi-1000h],eax ; restore page0[0]
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pascal@23996
|
324 mov esi,cr3 ; reload TLB cache
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pascal@23996
|
325 mov cr3,esi ;
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pascal@23996
|
326 ; Return
|
pascal@19907
|
327 vcpi_ret:
|
pascal@23996
|
328 ret
|
pascal@23996
|
329
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pascal@23996
|
330 endp vcpi_pm_copy_routine
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pascal@23996
|
331
|
pascal@23996
|
332
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pascal@23996
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333 ;***************************************************************
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pascal@23996
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334 ;void _vm2rm();
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pascal@23996
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335 ;***************************************************************
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pascal@23996
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336 ;****** Uses: Flags
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pascal@23996
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337 ;***************************************************************
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pascal@23996
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338 global _vm2rm:near
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pascal@23996
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339 proc _vm2rm near
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pascal@23996
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340
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pascal@23996
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341 assume cs:DGROUP,ds:DGROUP
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pascal@23996
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342 extrn sssp:dword
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pascal@23996
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343 ifdef NO386
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pascal@23996
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344 p8086
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pascal@23996
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345 extrn _vcpi:byte
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pascal@23996
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346 mov bx,offset sssp
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pascal@23996
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347 test [_vcpi],bh
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pascal@23996
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348 jz vcpi_ret
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pascal@23996
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349 else
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pascal@23996
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350 p386
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pascal@23996
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351 smsw ax ;SMSW cannot be trapped! :-)
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pascal@23996
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352 and al,1 ;MSW_PE
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pascal@23996
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353 jz vcpi_ret
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pascal@23996
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354 mov bx,offset sssp
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pascal@23996
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355 endif
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pascal@23996
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356 p386
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pascal@23999
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357 pop ax ; convert
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pascal@23999
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358 push cs ; near call
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pascal@23999
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359 push ax ; to far call
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pascal@23996
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360 push ds
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pascal@23996
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361 mov [bx],sp
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pascal@23996
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362 ;mov [bx+2],ss
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pascal@23996
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363
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pascal@23996
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364 call switch_to_pm ; EAX, EDX/ESI, DS, ES, FS, GS destroyed
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pascal@23996
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365 assume nothing
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pascal@23996
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366 assume cs:DGROUP
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pascal@23996
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367
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pascal@23996
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368 ; Now we are in 16-bit protected mode
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pascal@23996
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369 ; Black magic here
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pascal@23996
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370 mov eax,cr0
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pascal@23996
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371 and eax,7ffffffeh ; clear PG,P bits
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pascal@23996
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372 mov cr0,eax ; look mommy, we're in rm now!
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pascal@23996
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373 mov cr3,eax ; flush TLB cache
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pascal@23996
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374
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pascal@23996
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375 ; Now we are in rm, but not yet: have to restore sregs:
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pascal@23996
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376 lss sp,[cs:bx] ; SS
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pascal@23996
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377 pop ds ; DS
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pascal@23996
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378 retf ; CS
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pascal@23996
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379
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pascal@23996
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380 endp _vm2rm
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pascal@23996
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381
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pascal@23996
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382 ends _TEXT
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pascal@23996
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383
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pascal@23996
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384 end
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pascal@23996
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385
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pascal@23996
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386 ;###### END OF FILE ############################################
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