wok annotate linld/stuff/src/_BEG.ASM @ rev 22204

linld: 8086 may load zImage (again)
author Pascal Bellard <pascal.bellard@slitaz.org>
date Mon Nov 11 12:29:56 2019 +0100 (2019-11-11)
parents f3a4853e3eef
children a31ec0e0df8e
rev   line source
pascal@19515 1 ;***************************************************************
pascal@19515 2 ;****** This file is distributed under GPL
pascal@19515 3 ;***************************************************************
pascal@19515 4 ideal
pascal@21984 5 %PAGESIZE 1000
pascal@19515 6 %crefref
pascal@19515 7 %noincl
pascal@19515 8 %nomacs
pascal@19636 9 p8086
pascal@19515 10
pascal@19515 11 group DGROUP _TEXT,_DATA,_BSS
pascal@19515 12 assume cs:DGROUP,ds:DGROUP
pascal@19515 13
pascal@19515 14 segment _TEXT byte public use16 'CODE'
pascal@20451 15 ends _TEXT
pascal@20451 16
pascal@20451 17 segment _DATA byte public use16 'DATA'
pascal@20451 18 global _data_start:byte
pascal@20451 19 label _data_start byte
pascal@20451 20 ifndef NO386
pascal@22183 21 msg_badcpu db "I need 386+ CPU in real mode w/o paging"
pascal@22183 22 db " or "
pascal@22183 23 msg_badmapping db "under VCPI 4.0+ manager with low 640k 1:1 mapping"
pascal@22183 24 global _vcpi:byte
pascal@22183 25 _vcpi db 0
pascal@20451 26 endif
pascal@20451 27
pascal@20451 28 ends _DATA
pascal@20451 29
pascal@20451 30 segment _BSS byte public use16 'BSS'
pascal@21757 31
pascal@21757 32 STACK_SIZE = 1024
pascal@21757 33
pascal@20451 34 global _bss_start:byte
pascal@20451 35 label _bss_start byte
pascal@22170 36 global _version_string:byte
pascal@22170 37 label _version_string byte
pascal@21757 38 db STACK_SIZE-2 dup(?)
pascal@21757 39 stktop dw ?
pascal@22183 40 ifdef NO386
pascal@22183 41 global _cpu386:byte
pascal@22183 42 _cpu386 db ?
pascal@22183 43 org $-1
pascal@22183 44 endif
pascal@20451 45 global _cpu_features:dword
pascal@20451 46 _cpu_features dd ?
pascal@20451 47 ends _BSS
pascal@20451 48
pascal@20451 49 segment _TEXT byte public use16 'CODE'
pascal@19515 50
pascal@19825 51 macro cpuid
pascal@19825 52 db 0fh,0A2h
pascal@19825 53 endm
pascal@19825 54
pascal@19515 55 org 100h
pascal@19515 56 global _text_start:byte
pascal@19515 57 label _text_start byte
pascal@19546 58
pascal@19515 59 ;***************************************************************
pascal@19515 60 ; clear bss
pascal@19515 61 ;***************************************************************
pascal@21757 62 mov sp,offset stktop
pascal@22179 63 mov si,offset _bss_start
pascal@20457 64 mov bx, 0F000h ; cld ; cli & empty string
pascal@19515 65 clearbss:
pascal@20451 66 mov [si],bl ; clear bss + heap + sp
pascal@20426 67 inc si
pascal@19546 68 jne clearbss
pascal@19546 69
pascal@19546 70 ;***************************************************************
pascal@19546 71 ; check CPU
pascal@19546 72 ;***************************************************************
pascal@19546 73
pascal@19546 74 ; Check for oldies
pascal@19873 75 push bx ; < 286 : flags[12..15] are forced 1
pascal@19873 76 popf ; = 286 : flags[12..15] are forced 0
pascal@19873 77 pushf ; > 286 : only flags[15] is forced 0
pascal@19873 78 pop dx
pascal@20451 79 add dh,bh ; NS=386+, S+NC=286, S+C=86/186
pascal@20451 80 ifndef NO386
pascal@19873 81 mov bx,offset msg_badcpu
pascal@22183 82 js godie ;it is not a 386+, die
pascal@20451 83 else
pascal@22183 84 js endcpu86 ;it is not a 386+, try ELKS & co
pascal@19546 85 endif
pascal@19636 86 p386
pascal@19546 87 ; Check for vm
pascal@19546 88 smsw ax ;SMSW cannot be trapped! :-)
pascal@19571 89 and al,1 ;MSW_PE
pascal@19546 90 ; We're in vm
pascal@20457 91 jnz check_vcpi
pascal@20457 92
pascal@20457 93 check_rm_paging:
pascal@20457 94 ; It's a 386 in real mode, chk for paging (crazy but possible)
pascal@20457 95 mov eax,cr0
pascal@20457 96 inc eax ;CR0_PG to S
pascal@20457 97 jns endcpu386
pascal@22183 98 ifndef NO386
pascal@20457 99 p8086
pascal@20457 100 extrn die:near
pascal@20457 101 godie:
pascal@22183 102 no_vcpi:
pascal@20457 103 call near die
pascal@22183 104 else
pascal@22183 105 jmp endcpu86
pascal@22183 106 endif
pascal@19546 107
pascal@19546 108 ;***************************************************************
pascal@19546 109 ; checks for vcpi
pascal@19546 110 ;***************************************************************
pascal@19546 111 label check_vcpi near
pascal@20457 112 p386
pascal@19546 113 push ds
pascal@19546 114 ; Check whether it is safe to call 67h (we trust only known EMM managers)
pascal@20426 115 push si
pascal@19546 116 pop ds
pascal@19546 117 mov ds,[word 67h*4+2]
pascal@20426 118 cmp [dword si+10+4],'0XXX'
pascal@19546 119 jne skip
pascal@19825 120 ;mov eax,'XMME'
pascal@20426 121 ;xor eax,[dword si+10]
pascal@19546 122 ; QMME also works (as told by <J.S.Peatfield@damtp.cambridge.ac.uk>)
pascal@19825 123 ;shl eax,8
pascal@19825 124 mov ax,'ME'
pascal@20426 125 xor ax,[word si+10]
pascal@19546 126 skip:
pascal@19546 127 pop ds
pascal@19546 128 jne no_vcpi
pascal@19546 129
pascal@19546 130 ; Check emm manager status and version
pascal@19571 131 ;mov ah,40h ; get status
pascal@19571 132 ;int 67h
pascal@22203 133 ;inc ax
pascal@22203 134 ;js no_vcpi
pascal@19546 135 mov ah,46h ; get version
pascal@19546 136 int 67h
pascal@22204 137 cmp ax,40h ; version must be >= 4.0
pascal@22203 138 jl no_vcpi ; btw check ax.15
pascal@19546 139 ; Check vcpi manager status
pascal@19546 140 ;;mov ax,5A01h ; ALLOCATE RAW PAGES
pascal@19546 141 ;;mov bx,4
pascal@19546 142 ;;int 67h
pascal@22203 143 ;;inc ax
pascal@22203 144 ;;js no_vcpi
pascal@19546 145 ;;push dx ;$ save handle
pascal@19546 146 mov ax,0DE00h ; check for vcpi present
pascal@19546 147 int 67h
pascal@19546 148 test ah,ah
pascal@19571 149 jnz no_vcpi
pascal@19546 150 is386vcpi:
pascal@19546 151 extrn prepare_vcpi:near
pascal@19546 152 call prepare_vcpi
pascal@19546 153 ; get_vcpi_interface() || die("VCPI: low 640k: need 1:1 mapping");
pascal@19546 154 ;extrn _get_vcpi_interface:near
pascal@19546 155 ;call _get_vcpi_interface
pascal@22183 156 ifndef NO386
pascal@19546 157 mov bx,offset msg_badmapping
pascal@20457 158 jnz no_vcpi
pascal@22183 159 dec [byte bx+_vcpi-msg_badmapping]
pascal@22183 160 else
pascal@22183 161 jnz no_vcpi
pascal@22183 162 extrn _vcpi:byte
pascal@22183 163 dec [byte _vcpi]
pascal@22183 164 endif
pascal@20457 165 endcpu386:
pascal@20457 166 pushfd
pascal@20457 167 pop dx
pascal@20457 168 pop ax
pascal@20457 169 mov bl,al
pascal@20457 170 xor al,20h ; toggle CPUID feature bit 21
pascal@20457 171 push ax
pascal@20457 172 push dx
pascal@20457 173 popfd
pascal@20457 174 pushfd
pascal@22203 175 pop dx ; dx.1=flags.1=1
pascal@20457 176 pop ax
pascal@20457 177 xor al,bl ; clear C
pascal@20457 178 je @@no_cpuid ; CPUID feature bit changed ?
pascal@20457 179 mov eax,80000001h ; Extended Processor Info and Feature Bits
pascal@20457 180 cpuid
pascal@22183 181 ifdef NO386
pascal@22204 182 mov dl,-1 ; set 386 flag
pascal@22203 183 db 66h ; mov [_cpu_features],edx
pascal@22203 184 @@no_cpuid:
pascal@22203 185 mov [word _cpu_features],dx ; dl != 0
pascal@22203 186 no_vcpi:
pascal@22203 187 else
pascal@20457 188 mov [_cpu_features],edx
pascal@20457 189 @@no_cpuid:
pascal@22203 190 endif
pascal@20457 191 endcpu86:
pascal@19636 192 p8086
pascal@19546 193
pascal@19515 194 ;***************************************************************
pascal@19515 195 ; build argv & argc
pascal@19515 196 ;***************************************************************
pascal@22203 197 extrn _bss_end:word
pascal@22203 198 mov di,offset _bss_end
pascal@22203 199 global _heap_top
pascal@22203 200 org $-2
pascal@22203 201 _heap_top dw ?
pascal@19546 202 ;xor ax,ax
pascal@19546 203 ;push ax ; envp (already cleared)
pascal@19546 204 ;mov [word di],ax ; argv[0] = 0 (idem)
pascal@19515 205 mov si,80h
pascal@19515 206 lodsb
pascal@19515 207 cmp al,7Eh
pascal@19515 208 jbe alok
pascal@19515 209 mov al,7Eh
pascal@19515 210 alok:
pascal@19546 211 cbw
pascal@19515 212 xchg ax,bx
pascal@19515 213 mov [bx+si],bh ; set eos
pascal@19515 214 argbuild:
pascal@20160 215 ifdef DEBUG
pascal@20142 216 p386
pascal@20142 217 pusha
pascal@20142 218 mov bx,si
pascal@20142 219 extrn puts:near
pascal@20142 220 call puts
pascal@20142 221 popa
pascal@20160 222 endif
pascal@19515 223 mov bx,2 ; argc * 2
pascal@19515 224 argeos:
pascal@20451 225 mov cx,1 ; look for a start of string
pascal@19515 226 mov [byte si-1],bh ; mark eos
pascal@19515 227 mov ah,20h ; space will be eos
pascal@19515 228 arglp:
pascal@19515 229 lodsb
pascal@19515 230 cmp al,0h
pascal@19515 231 je argdone
pascal@19515 232 cmp al,20h
pascal@19515 233 jb argeos
pascal@19515 234 cmp al,ah
pascal@19515 235 je argeos
pascal@19515 236 cmp al,27h
pascal@19515 237 je isargstr
pascal@19515 238 cmp al,22h
pascal@19515 239 je isargstr
pascal@20451 240 jcxz arglp ; not start of string
pascal@19515 241 dec si
pascal@19884 242 ;jmp newarg
pascal@20451 243 db 0BAh ; mov dx,im opcode
pascal@19515 244 isargstr:
pascal@19515 245 mov ah,al ; expected eos
pascal@19515 246 newarg:
pascal@19515 247 mov [word bx+di],si ; argv[argc++] = si
pascal@19515 248 inc bx
pascal@19515 249 inc bx
pascal@20451 250 dec cx
pascal@19515 251 jmp arglp
pascal@19515 252 argdone:
pascal@19515 253 ;mov [word bx+di],0 ; argv[argc] = 0
pascal@19546 254 lea ax,[bx+di+2]
pascal@19546 255 mov [_heap_top],ax
pascal@19515 256 push di ; argv
pascal@19515 257 shr bx,1
pascal@19515 258 push bx ; argc
pascal@19515 259 ifndef filearg
pascal@19515 260 mov bx,[di+2] ; argv[1]
pascal@20528 261 extrn openargs:near
pascal@20528 262 call near openargs
pascal@19515 263 jc argend
pascal@19515 264 pop bx ; trash argc, argv >> 1Kb !
pascal@19546 265 global read_cmdline:near
pascal@20528 266 pop cx ; sizemax=argv
pascal@19546 267 read_cmdline:
pascal@20528 268 mov dx,di
pascal@20528 269 push dx
pascal@19515 270 push ax
pascal@20528 271 xchg ax,bx
pascal@20528 272 extrn @read$cxdxbx:near ; read(fd=bx,buffer=dx,size=cx)
pascal@20528 273 call near @read$cxdxbx
pascal@19515 274 pop bx ; fd for close
pascal@19515 275 pop si ; si=buffer=argv
pascal@19515 276 add di,ax
pascal@19515 277 extrn close:near
pascal@19515 278 call near close
pascal@19515 279 jmp argbuild
pascal@19515 280 argend:
pascal@19515 281 endif
pascal@19515 282
pascal@19515 283 ;***************************************************************
pascal@21757 284 extrn _main:near
pascal@21757 285 call _main
pascal@21757 286 ;never return
pascal@19538 287
pascal@19515 288 ;***************************************************************
pascal@21757 289
pascal@19515 290 ends _TEXT
pascal@19515 291
pascal@19515 292
pascal@19515 293 end _text_start
pascal@19515 294
pascal@19515 295 ;###### END OF FILE ############################################