diff options
Diffstat (limited to 'purgatory/arch/i386/entry32-16.S')
| -rw-r--r-- | purgatory/arch/i386/entry32-16.S | 25 |
1 files changed, 15 insertions, 10 deletions
diff --git a/purgatory/arch/i386/entry32-16.S b/purgatory/arch/i386/entry32-16.S index aaf1273..c051aab 100644 --- a/purgatory/arch/i386/entry32-16.S +++ b/purgatory/arch/i386/entry32-16.S @@ -24,15 +24,20 @@ .balign 16 entry16: .code32 - /* Compute where I am running at */ - movl $entry16, %ebx + /* Compute where I am running at (assumes esp valid) */ + call 1f +1: popl %ebx + subl $(1b - entry16), %ebx /* Fixup my real mode segment */ movl %ebx, %eax shrl $4, %eax - movw %ax, 2 + realptr + movw %ax, (2 + realptr - entry16)(%ebx) /* Fixup the gdt */ + leal (gdt - entry16)(%ebx), %eax + movl %eax, (0x02 + gdt - entry16)(%ebx) + movl %ebx, %eax shll $16, %eax @@ -44,17 +49,17 @@ entry16: andl $0xff000000, %edx orl %edx, %ecx - orl %eax, 0x08 + gdt - orl %ecx, 0x0c + gdt - orl %eax, 0x10 + gdt - orl %ecx, 0x14 + gdt + orl %eax, (0x08 + gdt - entry16)(%ebx) + orl %ecx, (0x0c + gdt - entry16)(%ebx) + orl %eax, (0x10 + gdt - entry16)(%ebx) + orl %ecx, (0x14 + gdt - entry16)(%ebx) /* Setup the classic BIOS interrupt table at 0x0 */ - lidt idtptr + lidt (idtptr - entry16)(%ebx) /* Provide us with 16bit segments that we can use */ - lgdt gdt + lgdt (gdt - entry16)(%ebx) /* Note we don't disable the a20 line, (this shouldn't be required) * The code to do it is in kexec_test and it is a real pain. @@ -147,7 +152,7 @@ idtptr: gdt: /* 0x00 unusable segment so used as the gdt ptr */ .word gdt_end - gdt - 1 - .long gdt + .long 0 /* gdt */ .word 0 /* 0x08 16 bit real mode code segment */ |