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Debian release 0.5-2.

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gord committed 1999-02-22 03:10:37 +00:00
1 parent 6239c1ac50
commit b117211d4a
19 files changed
+652 -271
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shared_src/asm.S
+67 -220
View File
@@ -25,33 +25,23 @@
.text
/*
* The ".code16" directive only works in GAS, the GNU assembler!
* This adds 32-bit data or addressing directives so that this
* code will work in real mode!
*/
/* Tell GAS to generate 16-bit instructions so that this code works
in real mode. */
.code16
ENTRY(start)
/*
* "start" should be loaded at 0x0:$STARTADDR. This next
* is to guarantee that.
* Guarantee that "start" is loaded at 0x0:0x8000.
*/
/* ljmp $0, $codestart */
.byte 0xea
.word 0x8070, 0
/* padding */
.byte 0
ljmp $0, $(codestart - EXT_C(start) + 0x8000)
/*
* Compatibility version number
*
* These MUST be at byte offset 6 and 7 of the executable
*
* DO NOT MOVE !!!
*/
. = EXT_C(start) + 0x6
.byte COMPAT_VERSION_MAJOR, COMPAT_VERSION_MINOR
/*
@@ -77,7 +67,7 @@ VARIABLE(config_file)
. = EXT_C(start) + 0x70
/* the code continues... */
/* the real mode code continues... */
codestart:
cli /* we're not safe here! */
@@ -88,24 +78,23 @@ codestart:
movw %ax, %es
/* set up the real mode/BIOS stack */
movl $STACKOFF, %esp
movl $STACKOFF, %ebp
movl %ebp, %esp
sti /* we're safe again */
/* save boot drive reference */
addr32
movb %dl, EXT_C(boot_drive)
/* reset disk system (%ah = 0) */
int $13
int $0x13
/* transition to protected mode */
data32
call EXT_C(real_to_prot)
/*
* The ".code32" directive only works in GAS, the GNU assembler!
* This gets out of "16-bit" mode.
*/
/* The ".code32" directive takes GAS out of 16-bit mode. */
.code32
/*
@@ -169,20 +158,11 @@ ENTRY(chain_stage1)
movb EXT_C(boot_drive), %dl
call EXT_C(prot_to_real)
/*
* The ".code16" directive only works in GAS, the GNU assembler!
* This adds 32-bit data or addressing directives so that this
* code will work in real mode!
*/
.code16
data32
addr32
ljmp (offset)
/*
* The ".code32" directive only works in GAS, the GNU assembler!
* This gets out of "16-bit" mode.
*/
.code32
@@ -218,23 +198,14 @@ ENTRY(chain_stage2)
movb EXT_C(boot_drive), %dl
call EXT_C(prot_to_real)
/*
* The ".code16" directive only works in GAS, the GNU assembler!
* This adds 32-bit data or addressing directives so that this
* code will work in real mode!
*/
.code16
data32
addr32
ljmp (offset)
/*
* The ".code32" directive only works in GAS, the GNU assembler!
* This gets out of "16-bit" mode.
*/
.code32
/*
* These next two routines, "real_to_prot" and "prot_to_real" are structured
* in a very specific way. Be very careful when changing them.
@@ -243,16 +214,16 @@ ENTRY(chain_stage2)
*/
ENTRY(real_to_prot)
.code16
cli
/* load the GDT register */
addr32
data32
addr32
lgdt gdtdesc
/* turn on protected mode */
movl %cr0, %eax
data32
orl $CR0_PE_ON, %eax
movl %eax, %cr0
@@ -260,6 +231,12 @@ ENTRY(real_to_prot)
data32
ljmp $PROT_MODE_CSEG, $protcseg
/*
* The ".code32" directive only works in GAS, the GNU assembler!
* This gets out of "16-bit" mode.
*/
.code32
protcseg:
/* reload other segment registers */
movw $PROT_MODE_DSEG, %ax
@@ -318,9 +295,10 @@ ENTRY(prot_to_real)
ljmp $PSEUDO_RM_CSEG, $tmpcseg /* jump to a 16 bit segment */
tmpcseg:
.code16
/* clear the PE bit of CR0 */
movl %cr0, %eax
data32
andl $CR0_PE_OFF, %eax
movl %eax, %cr0
@@ -328,13 +306,6 @@ tmpcseg:
data32
ljmp $0, $realcseg
/*
* The ".code16" directive only works in GAS, the GNU assembler!
* This adds 32-bit data or addressing directives so that this
* code will work in real mode!
*/
.code16
realcseg:
/* we are in real mode now
* set up the real mode segment registers : DS, SS, ES
@@ -352,12 +323,9 @@ realcseg:
sti
/* return on new stack! */
data32
ret
/*
* The ".code32" directive only works in GAS, the GNU assembler!
* This gets out of "16-bit" mode.
*/
.code32
@@ -443,18 +411,13 @@ disk_use_standard_bios:
movw 0x1c(%ebp), %bx /* segment */
call EXT_C(prot_to_real) /* enter real mode */
/*
* The ".code16" directive only works in GAS, the GNU assembler!
* This adds 32-bit data or addressing directives so that this
* code will work in real mode!
*/
.code16
movw %bx, %es /* load segment */
/*
* Shift num sectors and subfunction back
*/
data32
shrl $16, %ebx
pushw %bx /* save num sectors */
xorw %bx, %bx
@@ -472,6 +435,7 @@ disk_loop:
movb $0, %bl
/* did we actually succeed? */
data32
jnc disk_exit_16
/* do we try again? */
@@ -479,18 +443,15 @@ disk_loop:
cmpw $0, %si
/* if this isn't the third try, go again */
data32
jne disk_loop
/* save return value */
movb %ah, %bl
disk_exit_16:
data32
call EXT_C(real_to_prot) /* back to protected mode */
/*
* The ".code32" directive only works in GAS, the GNU assembler!
* This gets out of "16-bit" mode.
*/
.code32
movb %bl, %al /* return value in %eax */
@@ -524,16 +485,11 @@ ENTRY(get_diskinfo)
movw 0x8(%ebp), %dx /* diskinfo(drive #) */
call EXT_C(prot_to_real) /* enter real mode */
/*
* The ".code16" directive only works in GAS, the GNU assembler!
* This adds 32-bit data or addressing directives so that this
* code will work in real mode!
*/
.code16
movb %dl, %al
andb $0x80, %al
data32
jnz hard_drive
/*
@@ -548,13 +504,12 @@ probe_loop:
int $0x13
incw %si
/* movb (%si), %cl */
.byte 0x8A, 0x0C
movb (%si), %cl
/* if number of sectors is 0, display error and die */
cmpb $0, %cl
data32
je probe_failed
/* perform read */
@@ -566,12 +521,14 @@ probe_loop:
movb $0, %dh
int $0x13
data32
jc probe_loop
/* %cl is already the correct value! */
movb $1, %dh
movb $79, %ch
data32
jmp probe_success
probe_values:
@@ -581,6 +538,7 @@ hard_drive:
movb $0x8, %ah /* ask for disk info */
int $0x13
data32
jc probe_failed
/* es:di = parameter table */
@@ -595,7 +553,8 @@ probe_success:
* 8 bit sector
*/
movb %cl, %al /* Upper two bits of cylinder count */
andl $192,%eax
andl $192,%eax
addr32
leal 0(,%eax,4),%eax /* << 2 */
movb %ch, %al /* Lower 8 bits */
sall $16,%eax /* << 16 */
@@ -604,6 +563,7 @@ probe_success:
movb %cl, %al /* max sector (and # sectors) */
movl %eax, %ebx /* save return value */
data32
jmp got_drive
probe_failed:
@@ -617,12 +577,8 @@ probe_failed:
movl $0, %ebx /* not present value */
got_drive:
data32
call EXT_C(real_to_prot) /* back to protected mode */
/*
* The ".code32" directive only works in GAS, the GNU assembler!
* This gets out of "16-bit" mode.
*/
.code32
/* set up return in correct register */
@@ -668,12 +624,6 @@ ENTRY(putchar)
pc_notnewline:
call EXT_C(prot_to_real)
/*
* The ".code16" directive only works in GAS, the GNU assembler!
* This adds 32-bit data or addressing directives so that this
* code will work in real mode!
*/
.code16
movb %bl, %al
@@ -681,12 +631,8 @@ pc_notnewline:
movw $1, %bx
int $0x10
data32
call EXT_C(real_to_prot)
/*
* The ".code32" directive only works in GAS, the GNU assembler!
* This gets out of "16-bit" mode.
*/
.code32
pop %ebx
@@ -712,18 +658,14 @@ ENTRY(get_memsize)
mov 0xc(%esp), %ebx
call EXT_C(prot_to_real) /* enter real mode */
/*
* The ".code16" directive only works in GAS, the GNU assembler!
* This adds 32-bit data or addressing directives so that this
* code will work in real mode!
*/
.code16
cmpb $0x1, %bl
data32
je xext
int $0x12
data32
jmp xdone
xext:
@@ -733,12 +675,8 @@ xext:
xdone:
movw %ax, %bx
data32
call EXT_C(real_to_prot)
/*
* The ".code32" directive only works in GAS, the GNU assembler!
* This gets out of "16-bit" mode.
*/
.code32
movw %bx, %ax
@@ -767,12 +705,6 @@ ENTRY(get_eisamemsize)
push %edx
call EXT_C(prot_to_real) /* enter real mode */
/*
* The ".code16" directive only works in GAS, the GNU assembler!
* This adds 32-bit data or addressing directives so that this
* code will work in real mode!
*/
.code16
movw $0xe801, %ax
@@ -781,12 +713,8 @@ ENTRY(get_eisamemsize)
shll $16, %ebx
movw %ax, %bx
data32
call EXT_C(real_to_prot)
/*
* The ".code32" directive only works in GAS, the GNU assembler!
* This gets out of "16-bit" mode.
*/
.code32
movl $0xFFFFFFFF, %eax
@@ -842,41 +770,36 @@ ENTRY(get_mem_map)
movl $0x534d4150, %edx
call EXT_C(prot_to_real) /* enter real mode */
/*
* The ".code16" directive only works in GAS, the GNU assembler!
* This adds 32-bit data or addressing directives so that this
* code will work in real mode!
*/
.code16
movw %si, %es
movw $0xe820, %ax
int $0x15
data32
jc xnosmap
cmpl $0x534d4150, %eax
data32
jne xnosmap
cmpl $0x14, %ecx
data32
jl xnosmap
cmpl $0x400, %ecx
data32
jg xnosmap
data32
jmp xsmap
xnosmap:
movl $0, %ecx
xsmap:
data32
call EXT_C(real_to_prot)
/*
* The ".code32" directive only works in GAS, the GNU assembler!
* This gets out of "16-bit" mode.
*/
.code32
/* write length of buffer (zero if error) into "addr" */
@@ -948,17 +871,19 @@ gloop2ret:
#ifdef DEBUG
ENTRY(patch_code) /* labels start with "pc_" */
.code16
ENTRY(patch_code) /* labels start with "pc_" */
mov %cs, %ax
mov %ax, %ds
mov %ax, %es
mov %ax, %fs
mov %ax, %gs
addr32
movl $0, 0
pc_stop:
hlt
data32
jmp pc_stop
ENTRY(patch_code_end)
@@ -1002,12 +927,6 @@ ENTRY(big_linux_boot)
movl %eax, offset
call EXT_C(prot_to_real)
/*
* The ".code16" directive only works in GAS, the GNU assembler!
* This adds 32-bit data or addressing directives so that this
* code will work in real mode!
*/
.code16
/* final setup for linux boot */
@@ -1017,12 +936,9 @@ ENTRY(big_linux_boot)
movw %ax, %ss
/* jump to start */
data32
addr32
ljmp (offset)
/*
* The ".code32" directive only works in GAS, the GNU assembler!
* This gets out of "16-bit" mode.
*/
.code32
@@ -1064,12 +980,6 @@ ENTRY(cls)
push %ebx /* save EBX */
call EXT_C(prot_to_real)
/*
* The ".code16" directive only works in GAS, the GNU assembler!
* This adds 32-bit data or addressing directives so that this
* code will work in real mode!
*/
.code16
movb $0xf, %ah
@@ -1077,12 +987,8 @@ ENTRY(cls)
xorb %ah, %ah
int $0x10 /* Set Video mode (clears screen) */
data32
call EXT_C(real_to_prot)
/*
* The ".code32" directive only works in GAS, the GNU assembler!
* This gets out of "16-bit" mode.
*/
.code32
pop %ebx
@@ -1110,24 +1016,14 @@ ENTRY(getxy)
push %edx
call EXT_C(prot_to_real)
/*
* The ".code16" directive only works in GAS, the GNU assembler!
* This adds 32-bit data or addressing directives so that this
* code will work in real mode!
*/
.code16
xorb %bh, %bh /* set page to 0 */
movb $0x3, %ah
int $0x10 /* get cursor position */
data32
call EXT_C(real_to_prot)
/*
* The ".code32" directive only works in GAS, the GNU assembler!
* This gets out of "16-bit" mode.
*/
.code32
movb %dl, %ah
@@ -1160,24 +1056,14 @@ ENTRY(gotoxy)
movb 0x18(%esp), %dh /* %dh = y */
call EXT_C(prot_to_real)
/*
* The ".code16" directive only works in GAS, the GNU assembler!
* This adds 32-bit data or addressing directives so that this
* code will work in real mode!
*/
.code16
xorb %bh, %bh /* set page to 0 */
movb $0x2, %ah
int $0x10 /* set cursor position */
data32
call EXT_C(real_to_prot)
/*
* The ".code32" directive only works in GAS, the GNU assembler!
* This gets out of "16-bit" mode.
*/
.code32
pop %edx
@@ -1232,12 +1118,6 @@ ENTRY(set_attrib)
xorl %ebx, %ebx
call EXT_C(prot_to_real)
/*
* The ".code16" directive only works in GAS, the GNU assembler!
* This adds 32-bit data or addressing directives so that this
* code will work in real mode!
*/
.code16
movb $0x8, %ah
@@ -1247,12 +1127,8 @@ ENTRY(set_attrib)
movw $1, %cx
int $0x10
data32
call EXT_C(real_to_prot)
/*
* The ".code32" directive only works in GAS, the GNU assembler!
* This gets out of "16-bit" mode.
*/
.code32
pop %ecx
@@ -1286,27 +1162,18 @@ ENTRY(getrtsecs)
push %edx
call EXT_C(prot_to_real) /* enter real mode */
/*
* The ".code16" directive only works in GAS, the GNU assembler!
* This adds 32-bit data or addressing directives so that this
* code will work in real mode!
*/
.code16
movb $0x2, %ah
int $0x1a
data32
jnc gottime
movb $0xff, %dh
gottime:
data32
call EXT_C(real_to_prot)
/*
* The ".code32" directive only works in GAS, the GNU assembler!
* This gets out of "16-bit" mode.
*/
.code32
movb %dh, %al
@@ -1330,24 +1197,14 @@ ENTRY(asm_getkey)
push %ebx /* save %ebx */
call EXT_C(prot_to_real)
/*
* The ".code16" directive only works in GAS, the GNU assembler!
* This adds 32-bit data or addressing directives so that this
* code will work in real mode!
*/
.code16
int $0x16
movw %ax, %bx /* real_to_prot uses %eax */
data32
call EXT_C(real_to_prot)
/*
* The ".code32" directive only works in GAS, the GNU assembler!
* This gets out of "16-bit" mode.
*/
.code32
movw %bx, %ax
@@ -1377,31 +1234,23 @@ ENTRY(checkkey)
xorl %ebx, %ebx
call EXT_C(prot_to_real) /* enter real mode */
/*
* The ".code16" directive only works in GAS, the GNU assembler!
* This adds 32-bit data or addressing directives so that this
* code will work in real mode!
*/
.code16
movb $0x1, %ah
int $0x16
data32
jz notpending
movw %ax, %bx
data32
jmp pending
notpending:
movl $0xFFFFFFFF, %ebx
pending:
data32
call EXT_C(real_to_prot)
/*
* The ".code32" directive only works in GAS, the GNU assembler!
* This gets out of "16-bit" mode.
*/
.code32
mov %ebx, %eax
@@ -1477,5 +1326,3 @@ gdt:
gdtdesc:
.word 0x27 /* limit */
.long gdt /* addr */