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|
/******************************************************************************
* cmdline.S
*
* Early command-line parsing.
*/
.code32
#include "video.h"
# NB. String pointer on stack is modified to point past parsed digits.
.Latoi:
push %ebx
push %ecx
push %edx
push %esi
xor %ebx,%ebx /* %ebx = accumulator */
mov $10,%ecx /* %ecx = base (default base 10) */
mov 16+4(%esp),%esi /* %esi = pointer into ascii string. */
lodsb
cmpb $'0',%al
jne 2f
mov $8,%ecx /* Prefix '0' => octal (base 8) */
lodsb
cmpb $'x',%al
jne 2f
mov $16,%ecx /* Prefix '0x' => hex (base 16) */
1: lodsb
2: sub $'0',%al
jb 4f
cmp $9,%al
jbe 3f
sub $'A'-'0'-10,%al
jb 4f
cmp $15,%al
jbe 3f
sub $'a'-'A',%al
jb 4f
3: cmp %cl,%al
jae 4f
movzbl %al,%eax
xchg %eax,%ebx
mul %ecx
xchg %eax,%ebx
add %eax,%ebx
jmp 1b
4: mov %ebx,%eax
dec %esi
mov %esi,16+4(%esp)
pop %esi
pop %edx
pop %ecx
pop %ebx
ret
.Lstrstr:
push %ecx
push %edx
push %esi
push %edi
xor %eax,%eax
xor %ecx,%ecx
not %ecx
mov 16+4(%esp),%esi
mov 16+8(%esp),%edi
repne scasb
not %ecx
dec %ecx
mov %ecx,%edx
1: mov 16+8(%esp),%edi
mov %esi,%eax
mov %edx,%ecx
repe cmpsb
je 2f
xchg %eax,%esi
inc %esi
cmpb $0,-1(%eax)
jne 1b
xor %eax,%eax
2: pop %edi
pop %esi
pop %edx
pop %ecx
ret
.Lstr_prefix:
push %esi
push %edi
mov 8+4(%esp),%esi /* 1st arg is prefix string */
mov 8+8(%esp),%edi /* 2nd arg is main string */
1: lodsb
test %al,%al
jz 2f
scasb
je 1b
sbb %eax,%eax
or $1,%al
jmp 3f
2: xor %eax,%eax
3: pop %edi
pop %esi
ret
.Lstrlen:
push %ecx
push %esi
push %edi
xor %eax,%eax
xor %ecx,%ecx
not %ecx
mov 12+4(%esp),%edi
repne scasb
not %ecx
dec %ecx
mov %ecx,%eax
pop %edi
pop %esi
pop %ecx
ret
.Lfind_option:
mov 4(%esp),%eax
dec %eax
push %ebx
1: pushl 4+8(%esp)
inc %eax
push %eax
call .Lstrstr
add $8,%esp
test %eax,%eax
jz 3f
cmp %eax,4+4(%esp)
je 2f
cmpb $' ',-1(%eax)
jne 1b
2: mov %eax,%ebx
pushl 4+8(%esp)
call .Lstrlen
add $4,%esp
xadd %eax,%ebx
cmpb $'\0',(%ebx)
je 3f
cmpb $' ',(%ebx)
je 3f
cmpb $'=',(%ebx)
jne 1b
3: pop %ebx
ret
cmdline_parse_early:
pusha
/* Bail if there is no command line to parse. */
mov sym_phys(multiboot_ptr),%ebx
mov MB_flags(%ebx),%eax
test $4,%al
jz .Lcmdline_exit
mov MB_cmdline(%ebx),%eax
test %eax,%eax
jz .Lcmdline_exit
/* Check for 'no-real-mode' command-line option. */
pushl $sym_phys(.Lno_rm_opt)
pushl MB_cmdline(%ebx)
call .Lfind_option
test %eax,%eax
setnz %al
or %al,sym_phys(skip_realmode)
/* Check for 'tboot=' command-line option. */
movl $sym_phys(.Ltboot_opt),4(%esp)
call .Lfind_option
test %eax,%eax
setnz %al
or %al,sym_phys(skip_realmode) /* tboot= implies no-real-mode */
.Lparse_edd:
/* Check for 'edd=' command-line option. */
movl $sym_phys(.Ledd_opt),4(%esp)
call .Lfind_option
test %eax,%eax
jz .Lparse_edid
cmpb $'=',3(%eax)
jne .Lparse_edid
add $4,%eax
movb $2,sym_phys(opt_edd) /* opt_edd=2: edd=off */
cmpw $0x666f,(%eax) /* 0x666f == "of" */
je .Lparse_edid
decb sym_phys(opt_edd) /* opt_edd=1: edd=skipmbr */
cmpw $0x6b73,(%eax) /* 0x6b73 == "sk" */
je .Lparse_edid
decb sym_phys(opt_edd) /* opt_edd=0: edd=on (default) */
.Lparse_edid:
/* Check for 'edid=' command-line option. */
movl $sym_phys(.Ledid_opt),4(%esp)
call .Lfind_option
test %eax,%eax
jz .Lparse_vga
cmpb $'=',4(%eax)
jne .Lparse_vga
add $5,%eax
mov %eax,%ebx
push %ebx
pushl $sym_phys(.Ledid_force)
call .Lstr_prefix
add $8,%esp
movb $2,sym_phys(opt_edid) /* opt_edid=2: edid=force */
test %eax,%eax
jz .Lparse_vga
push %ebx
pushl $sym_phys(.Ledid_no)
call .Lstr_prefix
add $8,%esp
decb sym_phys(opt_edid) /* opt_edid=1: edid=no */
test %eax,%eax
jz .Lparse_vga
decb sym_phys(opt_edid) /* opt_edid=0: default */
.Lparse_vga:
/* Check for 'vga=' command-line option. */
movl $sym_phys(.Lvga_opt),4(%esp)
call .Lfind_option
add $8,%esp
test %eax,%eax
jz .Lcmdline_exit
cmpb $'=',3(%eax)
jne .Lcmdline_exit
add $4,%eax
/* Found the 'vga=' option. Default option is to display vga menu. */
movw $ASK_VGA,sym_phys(boot_vid_mode)
/* Check for 'vga=text-80x<rows>. */
mov %eax,%ebx
push %ebx
pushl $sym_phys(.Lvga_text80)
call .Lstr_prefix
add $8,%esp
test %eax,%eax
jnz .Lparse_vga_gfx
/* We have 'vga=text-80x<rows>'. */
add $8,%ebx
push %ebx
call .Latoi
add $4,%esp
mov %ax,%bx
lea sym_phys(.Lvga_text_modes),%esi
1: lodsw
test %ax,%ax
jz .Lcmdline_exit
cmp %ax,%bx
lodsw
jne 1b
mov %ax,sym_phys(boot_vid_mode)
jmp .Lcmdline_exit
.Lparse_vga_gfx:
/* Check for 'vga=gfx-<width>x<height>x<depth>'. */
push %ebx
pushl $sym_phys(.Lvga_gfx)
call .Lstr_prefix
add $8,%esp
test %eax,%eax
jnz .Lparse_vga_mode
/* We have 'vga=gfx-<width>x<height>x<depth>'. */
/* skip 'gfx-' */
add $4,%ebx
/* parse <width> */
push %ebx
call .Latoi
pop %esi
mov %ax,sym_phys(vesa_size)+0
/* skip 'x' */
lodsb
cmpb $'x',%al
jne .Lcmdline_exit
/* parse <height> */
push %esi
call .Latoi
pop %esi
mov %ax,sym_phys(vesa_size)+2
/* skip 'x' */
lodsb
cmpb $'x',%al
jne .Lcmdline_exit
/* parse <depth> */
push %esi
call .Latoi
pop %esi
mov %ax,sym_phys(vesa_size)+4
/* commit to vesa mode */
movw $VIDEO_VESA_BY_SIZE,sym_phys(boot_vid_mode)
jmp .Lcmdline_exit
.Lparse_vga_mode:
/* Check for 'vga=mode-<mode>'. */
push %ebx
pushl $sym_phys(.Lvga_mode)
call .Lstr_prefix
add $8,%esp
test %eax,%eax
jnz .Lparse_vga_current
/* We have 'vga=mode-<mode>'. */
add $5,%ebx
push %ebx
call .Latoi
add $4,%esp
mov %ax,sym_phys(boot_vid_mode)
jmp .Lcmdline_exit
.Lparse_vga_current:
/* Check for 'vga=current'. */
push %ebx
pushl $sym_phys(.Lvga_current)
call .Lstr_prefix
add $8,%esp
test %eax,%eax
jnz .Lcmdline_exit
/* We have 'vga=current'. */
movw $VIDEO_CURRENT_MODE,sym_phys(boot_vid_mode)
.Lcmdline_exit:
popa
ret
.Lvga_text_modes: /* rows, mode_number */
.word 25,VIDEO_80x25
.word 50,VIDEO_80x50
.word 43,VIDEO_80x43
.word 28,VIDEO_80x28
.word 30,VIDEO_80x30
.word 34,VIDEO_80x34
.word 60,VIDEO_80x60
.word 0
.Lvga_opt:
.asciz "vga"
.Lvga_text80:
.asciz "text-80x"
.Lvga_gfx:
.asciz "gfx-"
.Lvga_mode:
.asciz "mode-"
.Lvga_current:
.asciz "current"
.Lno_rm_opt:
.asciz "no-real-mode"
.Ltboot_opt:
.asciz "tboot"
.Ledid_opt:
.asciz "edid"
.Ledid_force:
.asciz "force"
.Ledid_no:
.asciz "no"
.Ledd_opt:
.asciz "edd"
|
