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pascal@19538
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1 ;***************************************************************
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pascal@19538
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2 ;****** This file is distributed under GPL
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pascal@19538
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3 ;***************************************************************
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pascal@19538
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4 ;VDPI init:
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pascal@19538
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5 ;Call char* prepare_vcpi(void *pagebuf) first to
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pascal@19538
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6 ;initialize paging tables needed for vm86.
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pascal@19538
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7 ;pagebuf needs to be 8k+4 bytes. Returns ptr to 1st unused byte.
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pascal@19538
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8 ;Then call int get_vcpi_interface(). Returns 1 if ok, 0 if bad.
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pascal@19538
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9 ;
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pascal@19538
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10 ;VCPI use:
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pascal@19538
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11 ;u32* malloc_vcpi(u32 size) - source in HIMEM.CPP
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pascal@19538
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12 ; Returns ptr to mallocated zero-terminated list of 4k page addrs
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pascal@19538
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13 ; Addresses are sorted in ascending order
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pascal@19538
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14 ; Never fails (will die if not enough mem)
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pascal@19538
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15 ;void read2vcpi(int fd, u32* vp, u32 size,
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pascal@19538
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16 ;void* xfer_buf, u16 xfer_size) - source in HIMEM.CPP
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pascal@19538
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17 ; Reads opened fd data into malloc_vcpi'ed memory
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pascal@19538
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18 ; Dies if file isn't exactly 'size' bytes long
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pascal@19538
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19 ; Needs intermediate buffer of exactly Nx4k bytes
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pascal@19538
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20 ;void memcpy_vcpi(u32 dstofs,u16 srcseg,u32 srcofs)
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pascal@19538
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21 ; copies 4k from conventional memory to VCPI
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pascal@19538
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22 ;void _vm2rm()
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pascal@19538
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23 ; switches you from vm86 to plain real mode
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pascal@19538
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24
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pascal@19538
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25
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pascal@19538
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26 ideal
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pascal@19538
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27 %crefref
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pascal@19538
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28 %noincl
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pascal@19538
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29 %nomacs
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pascal@19538
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30 p386
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pascal@19538
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31
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pascal@19538
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32 ;****** Stuff for declaring descriptors
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pascal@19538
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33 struc descr
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pascal@19538
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34 limit dw ?
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pascal@19538
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35 base0 dw ?
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pascal@19538
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36 base16 db ?
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pascal@19538
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37 type db ?
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pascal@19538
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38 limit16 db ?
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pascal@19538
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39 base24 db ?
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pascal@19538
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40 ends descr
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pascal@19538
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41 macro descriptor name,typ,plevel,present,limit,gran,base
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pascal@19538
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42 ;;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@19538
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43 name descr <limit and 0ffffh,base ,0 ,typ or plevel or present,(limit shr 16) or gran,0 >
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pascal@19538
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44 endm
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pascal@19538
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45 ; decriptor types (bit0..4 of descr.type )
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pascal@19538
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46 tss386_avail = 09h
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pascal@19538
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47 data_seg = 00010000b ; data segment
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pascal@19538
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48 expand_down = 00000100b ; =1 limit counts down from base
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pascal@19538
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49 writable = 00000010b ; =1 if write access allowed to data segment
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pascal@19538
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50 code_seg = 00011000b ; code segment
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pascal@19538
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51 conforming = 00000100b ; =1 code can be accesses and executed at any PL
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pascal@19538
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52 readable = 00000010b ; =1 if code also can be read (cannot be ovwritten)
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pascal@19538
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53 ; privilege levels (bit5..6 of descr.type )
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pascal@19538
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54 priv0 = 00000000b
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pascal@19538
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55 priv1 = 00100000b
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pascal@19538
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56 priv2 = 01000000b
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pascal@19538
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57 priv3 = 01100000b
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pascal@19538
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58 ; segment present bit (bit7 of descr.type )
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pascal@19538
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59 is_present = 10000000b
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pascal@19538
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60 not_present = 00000000b
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pascal@19538
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61 ;definition of granularity ( bits6..7 in descr.limit16 )
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pascal@19538
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62 gran_byte = 00000000b
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pascal@19538
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63 gran_page = 10000000b ; 4k granularity
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pascal@19538
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64 use_16 = 00000000b
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pascal@19538
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65 use_32 = 01000000b
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pascal@19538
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66
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pascal@19538
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67 ;****** rm32,imm16 helpers
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pascal@19538
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68 macro addzx_e rm,i
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pascal@19538
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69 db 66h
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pascal@19538
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70 add rm,i
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pascal@19538
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71 dw 0
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pascal@19538
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72 endm
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pascal@19538
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73
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pascal@19538
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74
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pascal@19634
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75 group DGROUP _TEXT,_DATA,_BSS
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pascal@19538
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76 assume cs:DGROUP,ds:DGROUP
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pascal@19538
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77
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pascal@19538
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78 segment _DATA byte public use16 'DATA'
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pascal@19538
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79
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pascal@19538
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80 label gdt byte
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pascal@19538
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81 gdt_null descr <?> ;0000
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pascal@19538
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82 gdt_vcpi descr <?> ;0008
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pascal@19538
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83 gdt_vcpi2 descr <?> ;0010
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pascal@19538
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84 gdt_vcpi3 descr <?> ;0018
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pascal@19538
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85 descriptor gdt_abs ,(data_seg+writable),priv0,is_present,0fffffh,(gran_page+use_32),0
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pascal@19538
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86 ;Note: code/data segs must be flagged use16 (i.e. use ip/sp, not eip/esp)
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pascal@19538
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87 ;Note: base addrs will be fixed up in prepare_vcpi()
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pascal@19538
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88 descriptor gdt_code,(code_seg+readable),priv0,is_present,0fffffh,(gran_page+use_16),0
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pascal@19538
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89 descriptor gdt_data,(data_seg+writable),priv0,is_present,0fffffh,(gran_page+use_16),0
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pascal@19538
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90 descriptor gdt_tss ,tss386_avail ,priv0,is_present,0ffh ,gran_byte ,<offset tss>
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pascal@19538
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91 SEL_VCPI = (gdt_vcpi - gdt_null)
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pascal@19538
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92 SEL_TSS = (gdt_tss - gdt_null)
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pascal@19538
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93 SEL_ABS = (gdt_abs - gdt_null)
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pascal@19538
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94 SEL_CODE = (gdt_code - gdt_null)
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pascal@19538
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95 SEL_DATA = (gdt_data - gdt_null)
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pascal@19538
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96
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pascal@19538
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97 label gdtr pword
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pascal@19538
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98 gdt_lim dw 0ffffh
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pascal@19538
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99 gdt_base dw offset gdt,0
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pascal@19538
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100
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pascal@19538
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101 ;Note: layout dictated by vcpi api, don't rearrange!
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pascal@19538
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102 label sw2pm_params byte
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pascal@19538
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103 ;Note: base addrs will be fixed up in prepare_vcpi()
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pascal@19634
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104 label pagedir_laddr dword
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pascal@19906
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105 sw2pm_cr3 dd 1000h
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pascal@19538
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106 sw2pm_gdtr_ptr dw offset gdtr,0
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pascal@19538
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107 sw2pm_idtr_ptr dw offset idtr,0
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pascal@19538
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108 sw2pm_ldtr dw 0 ;we don't need it
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pascal@19538
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109 sw2pm_tr dw SEL_TSS ;vcpi thinks we need it... can't set to 0
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pascal@19634
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110 sw2pm_jumpaddr dd 0
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pascal@19538
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111 dw SEL_CODE
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pascal@19538
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112
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pascal@19634
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113 vcpi_pm_entry dd 0
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pascal@19634
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114 dw SEL_VCPI
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pascal@19634
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115
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pascal@19634
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116 label idtr pword
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pascal@19634
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117 idt_lim dw 03ffh ;we won't enable ints,
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pascal@19634
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118 idt_base dd 0 ; so let's leave it the same as for rm
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pascal@19634
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119
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pascal@19634
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120 ends _DATA
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pascal@19634
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121
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pascal@19634
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122 segment _BSS byte public use16 'BSS'
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pascal@19634
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123
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pascal@19538
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124 label saved_ss_sp dword
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pascal@19538
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125 saved_sp dw ?
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pascal@19538
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126 saved_ss dw ?
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pascal@19538
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127
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pascal@19634
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128 tss dd ?,? ;enough, we'll never use it anyway
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pascal@19538
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129
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pascal@19634
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130 ends _BSS
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pascal@19538
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131
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pascal@19538
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132 segment _TEXT byte public use16 'CODE'
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pascal@19538
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133
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pascal@19538
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134 ;***************************************************************
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pascal@19538
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135 ;char* prepare_vcpi(void *pagebuf);
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pascal@19538
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136 ;****** Return: AX=>first unused byte in pagebuf
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pascal@19538
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137 ;****** Uses: Flags
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pascal@19538
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138 ;***************************************************************
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pascal@19538
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139 global _prepare_vcpi:near
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pascal@19538
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140 global prepare_vcpi:near
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pascal@19538
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141 proc _prepare_vcpi near
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pascal@19538
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142
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pascal@19538
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143 ;pop ax
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pascal@19538
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144 ;pop bx ;pgbuf
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pascal@19538
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145 ;push bx
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pascal@19538
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146 ;push ax
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pascal@19538
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147 prepare_vcpi:
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pascal@19538
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148
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pascal@19538
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149 ;Calculate pagedir/page0 addrs, initialize cr3 and pagedir[0]
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pascal@19538
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150 xor eax,eax
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pascal@19538
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151 ; heap_top = prepare_vcpi(malloc_or_die(8*1024+4));
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pascal@19538
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152 mov cx,8*1024+4
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pascal@19538
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153 extrn malloc_or_die:near
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pascal@19919
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154 call malloc_or_die ;keep cx
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pascal@19538
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155
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pascal@19538
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156 mov edx,cs
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pascal@19634
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157 shl edx,cl ;edx = linear addr of CS
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pascal@19634
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158 mov si,offset gdt_vcpi
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pascal@19538
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159 ; Fix up base of some gdt descriptors
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pascal@19538
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160 ; Note: 'add [dword xx.base0],edx' actually updates 24 bit quantity!
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pascal@19538
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161 ; Do NOT replace with mov!
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pascal@19919
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162 mov ebx,10000h-28h
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pascal@19906
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163 add [dword bx+si+sw2pm_idtr_ptr-gdt_vcpi+28h],edx
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pascal@19634
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164 @@fixup:
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pascal@19906
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165 add [dword bx+si+(gdt_code.base0)-gdt_vcpi+28h],edx
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pascal@19919
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166 add bx,8
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pascal@19906
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167 js @@fixup
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pascal@19919
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168 mov bh,10h
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pascal@19538
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169 add eax,edx
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pascal@19919
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170 and ax,0f000h ;eax = 4k aligned linear addr of pagebuf
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pascal@19919
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171 add eax,ebx ;eax=page0 linear addr
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pascal@19906
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172 add [si+sw2pm_cr3-gdt_vcpi],eax
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pascal@19919
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173 mov edi,eax
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pascal@19919
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174 sub edi,edx
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pascal@19538
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175 mov al,3 ;add present+writable bits
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pascal@19919
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176 mov [bx+di],eax ;stuff it into pagedir[0]
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pascal@19634
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177 push ds
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pascal@19919
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178 pop es ;es:di->page0,es:di+1000h->pagedir
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pascal@19538
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179 ;page directory will use only one entry (4 bytes):
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pascal@19538
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180 ;cr3 => pagedir => page0 => ########
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pascal@19538
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181 ; (1 entry) (1024 => # 4M #
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pascal@19538
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182 ; entries)=> # page #
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pascal@19538
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183 ; => ########
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pascal@19538
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184 ; Return
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pascal@19919
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185 lea ax,[bx+di+4]
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pascal@19538
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186 extrn _heap_top:word
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pascal@19538
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187 mov [_heap_top],ax
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pascal@19538
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188 ;ret
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pascal@19538
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189
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pascal@19538
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190 endp _prepare_vcpi
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pascal@19538
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191
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pascal@19538
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192
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pascal@19538
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193 ;***************************************************************
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pascal@19538
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194 ;int get_vcpi_interface();
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pascal@19634
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195 ;****** Return: Z - page mapping for low 640k is 1:1
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pascal@19634
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196 ;****** NZ - otherwise (it's bad)
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pascal@19538
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197 ;****** Uses: Flags
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pascal@19538
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198 ;***************************************************************
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pascal@19538
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199 global _get_vcpi_interface:near
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pascal@19538
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200 proc _get_vcpi_interface near
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pascal@19538
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201
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pascal@19538
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202 ;push si di
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pascal@19538
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203
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pascal@19538
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204 ; Get and save VCPI pm interface
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pascal@19634
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205 ;mov si,offset gdt_vcpi ;DS:DI => 3 GDT entries for VCPI
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pascal@19546
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206 ;mov di,[si+page0_ofs-gdt_vcpi] ;ES:DI => page0
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pascal@19546
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207 ;push ds
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pascal@19546
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208 ;pop es
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pascal@19634
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209 push di
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pascal@19538
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210 mov ax,0DE01h ;get vcpi pm interface
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pascal@19538
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211 int 67h
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pascal@19634
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212 xchg [vcpi_pm_entry],ebx ;clear ebx
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pascal@19634
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213 ;xor bx,bx
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pascal@19538
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214
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pascal@19538
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215 ; Check that mapping for low 640k is 1:1
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pascal@19634
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216 pop si ; [page0_ofs]
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pascal@19571
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217 ;cld
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pascal@19538
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218 @@map_chk:
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pascal@19538
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219 lodsd
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pascal@19538
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220 shr eax,12
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pascal@19538
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221 cmp ax,bx
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pascal@19538
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222 jne @@bad
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pascal@19538
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223 inc bx
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pascal@19634
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224 cmp al,((640*1024) shr 12)-1
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pascal@19538
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225 jne @@map_chk
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pascal@19538
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226 ; Return
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pascal@19538
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227 @@bad:
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pascal@19538
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228 ret
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pascal@19538
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229 endp _get_vcpi_interface
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pascal@19538
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230
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pascal@19538
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231
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pascal@19538
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232 ;***************************************************************
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pascal@19538
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233 ;void memcpy_vcpi(u32 dstofs,u16 srcseg,u32 srcofs);
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pascal@19538
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234 ;***************************************************************
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pascal@19538
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235 ;****** Copies PAGE_SIZE bytes
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pascal@19538
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236 ;****** Uses: Flags
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pascal@19538
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237 ;***************************************************************
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pascal@19538
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238 global call_pm_routine:near
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pascal@19538
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239 proc call_pm_routine near
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pascal@19538
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240
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pascal@19538
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241 arg dstofs :dword, \
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pascal@19538
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242 srcseg :word, \
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pascal@19538
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243 srcofs :dword = PARAM_SIZE
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pascal@19538
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244
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pascal@19538
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245 struc pm_regs
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pascal@19538
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246 $$retaddr dw ?
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pascal@19538
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247 $$f dw ?
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pascal@19538
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248 $$edi dd ?
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pascal@19538
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249 $$esi dd ?
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pascal@19538
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250 $$ebp dd ?
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pascal@19538
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251 $$esp dd ?
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pascal@19538
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252 $$ebx dd ?
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pascal@19538
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253 $$edx dd ?
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pascal@19538
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254 $$ecx dd ?
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pascal@19538
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255 $$eax dd ?
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pascal@19538
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256 ends
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pascal@19538
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257
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pascal@19538
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258 ;***************************************************************
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pascal@19538
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259 ;****** Helper: goes into 16bit pm and calls routine (addr on stk)
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pascal@19538
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260 ;***************************************************************
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pascal@19538
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261 mov bp,sp ; ss:bp => struct pm_regs
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pascal@19538
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262
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pascal@19538
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263 xor ax,ax ; IRET stack for return to vm
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pascal@19538
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264 push ax gs ; (9 dwords)
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pascal@19538
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265 push ax fs ;
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pascal@19538
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266 push ax ds ;
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pascal@19538
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267 push ax es ;
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pascal@19538
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268 push ax ss ;
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pascal@19538
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269 push ebp ; esp
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pascal@19538
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270 pushfd ; eflags: IF saved here
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pascal@19538
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271 push ax cs ;
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pascal@19538
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272 push ax ;\eip
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pascal@19538
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273 push offset @@vm_ret ;/
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pascal@19538
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274
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pascal@19538
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275 ;;mov [saved_xx],xx ;use if your vcpi trashes bp/etc
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pascal@19538
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276
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pascal@19634
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277 call switch_to_pm
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pascal@19634
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278
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pascal@19538
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279 ; Now we are in 16-bit protected mode
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pascal@19538
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280 mov ax,SEL_DATA
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pascal@19538
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281 mov ss,ax
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pascal@19538
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282 ;;mov ds,ax
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pascal@19538
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283 ;;mov es,ax
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pascal@19538
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284 ;;mov fs,ax
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pascal@19538
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285 ;;mov gs,ax
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pascal@19538
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286 assume nothing
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pascal@19538
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287 assume cs:DGROUP
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pascal@19538
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288
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pascal@19538
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289 ;;mov xx,[saved_xx] ;use if your vcpi trashes bp/etc
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pascal@19538
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290 lea sp,[bp-9*4] ;else we can do this trick with bp
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pascal@19538
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291
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pascal@19538
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292 ; Call the routine (bp points to params on stack if any)
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pascal@19538
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293 mov ax,[(pm_regs bp).$$f] ; ss:bp => struct pm_regs
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pascal@19538
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294 mov bp,[word (pm_regs bp).$$ebp] ;ss:bp => params
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pascal@19538
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295 call ax
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pascal@19538
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296
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pascal@19538
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297 ; Ok, let's return to vm
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pascal@19634
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298 mov ax,0DE0Ch ; maybe we need whole eax?
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pascal@19538
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299 cli ; to be safe
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pascal@19538
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300 clts ;
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pascal@19538
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301 push SEL_ABS ; vcpi wants ds=all_addrspace
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pascal@19538
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302 pop ds ;
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pascal@19538
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303 call [pword cs:vcpi_pm_entry]
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pascal@19538
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304 @@vm_ret:
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pascal@19538
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305 ; Now we are in vm86 mode. Sregs, esp, eflags (IF) restored from IRET stack
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pascal@19538
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306 ret
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pascal@19538
|
307
|
pascal@19538
|
308 ;***************************************************************
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pascal@19634
|
309 switch_to_pm:
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pascal@19634
|
310 assume cs:DGROUP,ds:DGROUP
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pascal@19634
|
311 pop [word sw2pm_jumpaddr]
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pascal@19634
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312 ;mov [word sw2pm_jumpaddr+2],0
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pascal@19634
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313 ;mov [word sw2pm_jumpaddr+4],SEL_CODE
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pascal@19634
|
314 mov esi,cs
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pascal@19634
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315 shl esi,4
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pascal@19634
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316 addzx_e si,<offset sw2pm_params>
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pascal@19634
|
317 mov ax,0DE0Ch ; vcpi: switch to pm
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pascal@19634
|
318 cli
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pascal@19634
|
319 int 67h
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pascal@19634
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320
|
pascal@19634
|
321 ;***************************************************************
|
pascal@19538
|
322 ;****** Helper: This is where real copy is done
|
pascal@19538
|
323 ;***************************************************************
|
pascal@19538
|
324 global do_memcpy_vcpi:near
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pascal@19538
|
325 label do_memcpy_vcpi near
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pascal@19538
|
326
|
pascal@19538
|
327 ; Note: ss:bp => params
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pascal@19538
|
328 ; Move data
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pascal@19634
|
329 mov ax,SEL_ABS
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pascal@19634
|
330 mov ds,ax
|
pascal@19634
|
331 mov es,ax
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pascal@19538
|
332 assume nothing
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pascal@19538
|
333 assume cs:DGROUP
|
pascal@19538
|
334
|
pascal@19538
|
335 ; Set up target addr:
|
pascal@19538
|
336 ; replace page mapping for page at 0 so
|
pascal@19538
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337 ; that it points to dstofs
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pascal@19538
|
338 mov eax,[dstofs]
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pascal@19538
|
339 mov al,03h ; writeable, present
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pascal@19634
|
340 call @@set_mapping
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pascal@19538
|
341 ;push eax ;X we'll need to restore mapping...
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pascal@19538
|
342 xor edi,edi ;es:edi => remapped page
|
pascal@19538
|
343
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pascal@19538
|
344 ; Set up source addr
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pascal@19538
|
345 mov esi,[srcofs]
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pascal@19538
|
346
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pascal@19538
|
347 ; Do copying
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pascal@19634
|
348 xor ecx,ecx
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pascal@19634
|
349 mov ch,4096/256
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pascal@19571
|
350 ;cld
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pascal@19538
|
351 ;; cmp esi,edi
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pascal@19538
|
352 ;; jae @@do_copy
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pascal@19538
|
353 ;; add esi,ecx ;src<dst: we must do
|
pascal@19538
|
354 ;; dec esi ; copy backwards to avoid
|
pascal@19538
|
355 ;; add edi,ecx ; overwrite bug
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pascal@19538
|
356 ;; dec edi ;
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pascal@19538
|
357 ;; std ;
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pascal@19538
|
358 ;;@@do_copy:
|
pascal@19538
|
359 db 67h ;address width override for esi/edi
|
pascal@19634
|
360 rep movsb
|
pascal@19538
|
361 ;; cld
|
pascal@19538
|
362
|
pascal@19538
|
363 ; Restore page mapping for page at 0
|
pascal@19538
|
364 ;pop eax ;X
|
pascal@19634
|
365 @@set_mapping:
|
pascal@19906
|
366 mov esi,[cs:sw2pm_cr3]
|
pascal@19906
|
367 xchg [esi-1000h],eax ; restore page0[0]
|
pascal@19538
|
368 mov ecx,cr3 ; reload TLB cache
|
pascal@19538
|
369 mov cr3,ecx ;
|
pascal@19538
|
370 ; Return
|
pascal@19907
|
371 vcpi_ret:
|
pascal@19538
|
372 ret
|
pascal@19538
|
373
|
pascal@19538
|
374 endp call_pm_routine
|
pascal@19538
|
375 assume cs:DGROUP,ds:DGROUP
|
pascal@19538
|
376
|
pascal@19538
|
377
|
pascal@19538
|
378 ;***************************************************************
|
pascal@19538
|
379 ;void _vm2rm();
|
pascal@19538
|
380 ;***************************************************************
|
pascal@19538
|
381 ;****** Uses: Flags
|
pascal@19538
|
382 ;***************************************************************
|
pascal@19538
|
383 global _vm2rm:near
|
pascal@19538
|
384 proc _vm2rm near
|
pascal@19538
|
385
|
pascal@19825
|
386 p8086
|
pascal@19580
|
387 extrn _vcpi:byte
|
pascal@19580
|
388 test [_vcpi],-1
|
pascal@19907
|
389 jz vcpi_ret
|
pascal@19825
|
390 p386
|
pascal@19907
|
391 pop ax
|
pascal@19907
|
392 push cs ;*
|
pascal@19907
|
393 push ax
|
pascal@19634
|
394 push si
|
pascal@19538
|
395 push ds
|
pascal@19538
|
396 mov [saved_ss],ss
|
pascal@19538
|
397 mov [saved_sp],sp
|
pascal@19538
|
398
|
pascal@19634
|
399 call switch_to_pm
|
pascal@19634
|
400
|
pascal@19538
|
401 ; Now we are in 16-bit protected mode
|
pascal@19538
|
402 mov ax,SEL_DATA ; load data sregs with limit >=64k
|
pascal@19538
|
403 mov ss,ax ; or you may get limit violations
|
pascal@19538
|
404 mov ds,ax ; later in rm
|
pascal@19634
|
405 ;mov es,ax ; (actually I prefer 4gig limits :-)
|
pascal@19571
|
406 ;mov fs,ax ;
|
pascal@19571
|
407 ;mov gs,ax ;
|
pascal@19538
|
408
|
pascal@19538
|
409 ; Black magic here
|
pascal@19538
|
410 mov eax,cr0
|
pascal@19538
|
411 and eax,7ffffffeh ; clear PG,P bits
|
pascal@19538
|
412 mov cr0,eax ; look mommy, we're in rm now!
|
pascal@19538
|
413 mov cr3,eax ; flush TLB cache
|
pascal@19538
|
414
|
pascal@19538
|
415 ; Now we are in rm, but not yet: have to restore sregs:
|
pascal@19538
|
416 lss sp,[saved_ss_sp]; SS
|
pascal@19538
|
417 pop ds ; DS
|
pascal@19907
|
418 pop si
|
pascal@19538
|
419 retf ; CS
|
pascal@19571
|
420
|
pascal@19538
|
421 endp _vm2rm
|
pascal@19538
|
422
|
pascal@19538
|
423 ends _TEXT
|
pascal@19538
|
424
|
pascal@19538
|
425 end
|
pascal@19538
|
426
|
pascal@19538
|
427 ;###### END OF FILE ############################################
|