wok-6.x annotate syslinux/stuff/iso2exe/bootiso.S @ rev 14257

syslinux/iso2exe: check kernel version, add floppy bootstrap stub
author Pascal Bellard <pascal.bellard@slitaz.org>
date Thu Mar 28 11:51:42 2013 +0100 (2013-03-28)
parents a26ba54f3ea7
children 5ed4d6b2d690
rev   line source
pascal@13691 1 .text
pascal@13691 2 .code16
pascal@13691 3 .org 0
pascal@13691 4
pascal@13691 5 CODESZ = 0x8000 // 16 sectors = 32Kb
pascal@13972 6 #define EXEADRS(x) x+0xC0
pascal@13972 7 #define EXESTR(x) x-0x40
pascal@13691 8
pascal@13691 9 .globl _start
pascal@13691 10 _start:
pascal@13691 11 decw %bp // Magic number: MZ
pascal@13691 12 popw %dx
pascal@13972 13 jmp start0 // Bytes on last page of file
pascal@13691 14 .word (CODESZ+511)/512 // Pages in file
pascal@13691 15 .word 0 // Relocations
pascal@13691 16 .word (end_header-_start)/16 // Size of header in paragraphs
pascal@13691 17 .word 4064-(CODESZ/16) // Minimum extra paragraphs needed
pascal@13691 18 .word 4064-(CODESZ/16) // Maximum extra paragraphs needed
pascal@13691 19 .word 0xFFF0 // Initial (relative) SS value
pascal@13691 20 .word 0xFFFE // Initial SP value
pascal@13691 21 .word 0 // Checksum
pascal@13729 22 .word EXEADRS(exestart) // Initial IP value
pascal@13691 23 .word 0xFFF0 // Initial (relative) CS value
pascal@13972 24 initramfssize:
pascal@13972 25 .word 0 // File address of relocation table
pascal@13972 26 id:
pascal@13691 27 .word 0 // Overlay number
pascal@14257 28 fdcnt:
pascal@14257 29 .byte 0 // Bootstrap floppy sector count
pascal@13691 30
pascal@13691 31 /////////////////////// Master Boot Record code //////////////////////////////
pascal@13691 32
pascal@13972 33 start0: // File address of relocation table
pascal@13691 34 pushw %dx // restore SP
pascal@13972 35 incw %bp // restore %bp
pascal@13713 36 pushw $0
pascal@13713 37 popw %ds
pascal@13713 38 movw $0x7C00, %bx
pascal@13713 39 pushfw
pascal@13713 40 pushw %ds
pascal@13713 41 pushw %bx
pascal@13691 42 pushaw
pascal@13691 43 movw %sp, %bp
pascal@13691 44 pushw %es
pascal@13972 45 cld
pascal@13972 46 pushw %ds
pascal@13972 47 popw %es
pascal@13691 48 call setreg
pascal@13691 49 rep
pascal@13691 50 movsw
pascal@13972 51 movw $0x80, %dx
pascal@13691 52 ljmp $0, $0x0600+start2
pascal@13972 53
pascal@13972 54 .org 60
pascal@13972 55 .long 0 // PE header offset
pascal@13972 56 end_header:
pascal@13972 57 chksum:
pascal@13972 58 .word 0
pascal@13972 59 comstart:
pascal@13972 60 .word 0
pascal@13691 61
pascal@13699 62 readsector2:
pascal@13699 63 incw %cx
pascal@13699 64 readsector1:
pascal@13699 65 movw %cx, (%bx)
pascal@13699 66 incw %cx
pascal@13699 67 movw $0x201, %ax
pascal@13699 68 int $0x13
pascal@13691 69 setreg:
pascal@13699 70 movw %bx, %si
pascal@13691 71 movw $0x0600, %di
pascal@13691 72 movw $0x0100, %cx
pascal@13691 73 return:
pascal@13691 74 ret
pascal@13691 75 start2:
pascal@13691 76 dxloop:
pascal@13699 77 call readsector1
pascal@13691 78 repe
pascal@13691 79 cmpsw
pascal@13691 80 je dxfound
pascal@13691 81 next:
pascal@13699 82 xorw %cx, %cx
pascal@13699 83 xchgw %ax, %dx
pascal@13699 84 addb $0x7D, %al // try every hard disk
pascal@13699 85 andb $0x83, %al // and floppy disk
pascal@13699 86 cmpb $0x80, %al
pascal@13699 87 xchgw %ax, %dx
pascal@13691 88 jnz dxloop
pascal@13691 89 fail:
pascal@13713 90 movw $0x0600+noloader, %si
pascal@13713 91 call putslp
pascal@13713 92 stop:
pascal@13713 93 hlt
pascal@13713 94 jmp stop
pascal@13691 95 dxfound:
pascal@13691 96 movw %dx, 10(%bp)
pascal@13699 97 call readsector2
pascal@13699 98 lodsw
pascal@13713 99 shrw $1, %ax
pascal@13699 100 jz fail // read fail or not isohydrid
pascal@13691 101 popw %es
pascal@13691 102 popa
pascal@13713 103 iret
pascal@13691 104
pascal@13713 105
pascal@13691 106 ////////////////////////////// DOS EXE code ///////////////////////////////////
pascal@13691 107
pascal@13713 108 help:
pascal@13729 109 .ascii "SliTaz GNU/L" // SliTaz GNU/Linux boot loader
pascal@13729 110 .byte EXESTR(iloader)
pascal@13713 111 no386:
pascal@13713 112 .ascii "No 386" // No 386+
pascal@13713 113 .byte EXESTR(plus)
pascal@13713 114 ERRvcpi:
pascal@13713 115 .ascii "No EMM386/VCPI 4" // No EMM386/VCPI 4.0+
pascal@13713 116 .byte EXESTR(dot0)
pascal@13713 117 chkerr:
pascal@13713 118 .ascii "Broken ISO image fil" // Broken ISO image file.
pascal@13713 119 .byte EXESTR(eeol)
pascal@13713 120 vm86modemsg:
pascal@13713 121 .ascii "vm86" // vm86 mode.
pascal@13713 122 .byte EXESTR(mode)
pascal@13713 123 rmPaging:
pascal@13713 124 .ascii "Invalid: paging + " // Invalid: paging + real mode.
pascal@13713 125 realmodemsg:
pascal@13713 126 .ascii "real" // real mode.
pascal@13972 127 // --------------- Must be in 00C0 013F range ------------------------
pascal@13713 128 mode:
pascal@13713 129 .ascii " mod"
pascal@13713 130 eeol:
pascal@13713 131 .ascii "e"
pascal@13713 132 .byte EXESTR(eol)
pascal@13713 133 noloader:
pascal@13729 134 .ascii "No isol" // No isolinux boot loader
pascal@13729 135 iloader:
pascal@13729 136 .ascii "inux boot loader"
pascal@13697 137 eol:
pascal@13713 138 .ascii "."
pascal@13713 139 eol2:
pascal@13713 140 .asciz "\r\n"
pascal@13691 141 noDOS3:
pascal@13713 142 .ascii "No DOS 3" // No DOS 3.0+
pascal@13713 143 dot0:
pascal@13713 144 .ascii ".0"
pascal@13713 145 plus:
pascal@13713 146 .ascii "+"
pascal@13713 147 .byte EXESTR(eol2)
pascal@13729 148 // -------------------------------------------------------------------
pascal@13697 149
pascal@13729 150 exestart:
pascal@13699 151 cld
pascal@13697 152 movw $0x100, %si
pascal@13713 153 movw -127(%si), %ax
pascal@13729 154 cwd // clear dx
pascal@13713 155 pushw %dx // dos exit
pascal@13713 156 cmpw $0x2F20, %ax
pascal@13729 157 movw $0x1000+EXESTR(help), %ax
pascal@13691 158 je abort
pascal@13729 159 pushfw // save flags
pascal@13729 160 // bits 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
pascal@13729 161 // flags 0 NT IOPL OF DF IF TF SF ZF 0 AF 0 PF 1 CF
pascal@13729 162 // movb $0x10, %ah
pascal@13729 163 pushw %ax
pascal@13729 164 popfw // < 286 : flags[12..15] are forced 1
pascal@13729 165 pushfw // = 286 : flags[12..15] are forced 0
pascal@13729 166 popw %cx // > 286 : only flags[15] is forced 0
pascal@13729 167 popfw // restore flags
pascal@13729 168 addb %ah, %ch // test F0 and 00 cases
pascal@13729 169 cmpb %ah, %ch
pascal@13729 170 movb $EXESTR(no386), %al
pascal@13729 171 jbe abort // C=8086/80186, Z=80286
pascal@13729 172 #if 1
pascal@13697 173 movw (%si), %cx
pascal@13729 174 jcxz is386
pascal@13729 175 #endif
pascal@13974 176 movw $(EXESTR(0x8000))/2, %cx
pascal@13697 177 chklp:
pascal@13697 178 lodsw
pascal@13697 179 addw %ax, %dx
pascal@13697 180 loop chklp
pascal@13713 181 movb $EXESTR(chkerr), %al
pascal@13729 182 je is386 // dx == 0 ?
pascal@13691 183 abort:
pascal@13691 184 puts:
pascal@13713 185 movb $1, %ah
pascal@13713 186 xchgw %ax, %si
pascal@13713 187 putslp:
pascal@13713 188 lodsb
pascal@13713 189 orb %al, %al
pascal@13713 190 jz moveret
pascal@13713 191 js puts
pascal@13713 192 movw $7, %bx
pascal@13713 193 movb $0xE, %ah
pascal@13713 194 int $0x10
pascal@13713 195 jmp putslp
pascal@13691 196
pascal@13691 197 is386:
pascal@13697 198 movl %cr0, %eax
pascal@13691 199 andb $1, %al
pascal@13691 200 jne tstvcpi
pascal@14150 201 incl %eax
pascal@13713 202 movb $EXESTR(rmPaging), %al
pascal@14150 203 js abort
pascal@13713 204 movb $EXESTR(realmodemsg), %al
pascal@13691 205 realmode:
pascal@13691 206 call puts
pascal@13699 207 movb $0x30, %ah
pascal@13699 208 int $0x21
pascal@13699 209 cmpb $3, %al
pascal@13713 210 movb $EXESTR(noDOS3), %al
pascal@13713 211 jb abort
pascal@13691 212 movw $moveend-move, %cx
pascal@13691 213 movw $0xC000, %di
pascal@14150 214 call move2
pascal@13691 215 move:
pascal@13691 216 movb $0x80, %ch
pascal@13691 217 movw $0x0100, %di
pascal@14150 218 pushw comstart-end_header(%di) // .com address
pascal@13691 219 move2:
pascal@14150 220 popw %si
pascal@13691 221 pushw %di
pascal@13691 222 rep
pascal@13691 223 movsb
pascal@13713 224 moveret:
pascal@13691 225 ret
pascal@13691 226 moveend:
pascal@13713 227
pascal@13713 228 VersionVCPI:
pascal@13713 229 cmpb $0x40, %dl // >= 4.0 ?
pascal@13713 230 jb NoVCPI
pascal@13713 231 movb $EXESTR(vm86modemsg), %al
pascal@13713 232 jmp realmode
pascal@13713 233 tstvcpi:
pascal@13713 234 pushw %ds
pascal@13713 235 movw %cx, %ds // %cx = 0
pascal@13713 236 movw 0x67*4+2, %ds
pascal@13713 237 movw $10, %si
pascal@14150 238 lodsl
pascal@13713 239 xorw $0x4D45, %ax // EM(MX) or EM(MQ)
pascal@14150 240 lodsl
pascal@13713 241 popw %ds
pascal@14150 242 jne NoVCPI
pascal@14150 243 xorl $0x30585858, %eax // XXX0
pascal@13713 244 movw $EXEADRS(CmdVCPI), %si
pascal@13713 245 ChkVCPI:
pascal@13713 246 NoVCPI:
pascal@13713 247 movb $EXESTR(ERRvcpi), %al
pascal@13713 248 jne abort
pascal@13713 249 lodsb
pascal@13713 250 shlw $8, %ax
pascal@13713 251 je VersionVCPI
pascal@13713 252 int $0x67
pascal@13713 253 testb %ah, %ah
pascal@14150 254 xchgw %ax, %dx
pascal@13713 255 jmp ChkVCPI
pascal@13713 256 CmdVCPI:
pascal@13713 257 .byte 0x40 // status
pascal@13713 258 .byte 0xDE // vcpi present ?
pascal@13713 259 .byte 0x46 // version
pascal@13713 260 .byte 0
pascal@13713 261
pascal@13691 262 .org 440
pascal@13691 263 //////////////////////////// partition table //////////////////////////////////
pascal@13691 264