karlos/fernlader2
7
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

Cleaned up the bios call code somewhat

Browse source
This commit is contained in:
Thomas Oltmann 2026-02-21 14:36:05 +01:00
parent c1737c30b7
commit 37f53699ff
3 changed files with 24 additions and 27 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

1
.gitignore vendored
View file

@ -1,4 +1,5 @@
*.o *.o
*.swp
/boot.bin /boot.bin
/boot.elf /boot.elf
/serve /serve

46
src/bios.S
View file

@ -31,8 +31,7 @@ bios_write: push %ebp
PROT32 PROT32
pop %ebx pop %ebx
mov %ebp, %esp leave
pop %ebp
ret ret
.global bios_getmap .global bios_getmap
@ -68,8 +67,7 @@ _gmdone: add $24, %di
pop %edi pop %edi
pop %ebx pop %ebx
mov %ebp, %esp leave
pop %ebp
ret ret
.global bios_func .global bios_func
@ -80,39 +78,38 @@ bios_func: push %ebp
push %edi push %edi
push %esi push %esi
mov 8+0(%ebp), %eax
mov 8+4(%ebp), %edi
// The interrupt number is given as an immediate value to INT. // The interrupt number is given as an immediate value to INT.
// To support any interrupt number, we use self-modifying code. // To support any interrupt number, we use self-modifying code.
mov 8+0(%ebp), %eax
mov %al, _bf_int+1 mov %al, _bf_int+1
PROT16 PROT16
REAL REAL
mov 0(%edi), %eax mov 8+4(%ebp), %edi
mov 4(%edi), %ecx mov 0(%edi), %ax
mov 8(%edi), %edx mov 2(%edi), %cx
mov 12(%edi), %ebx mov 4(%edi), %dx
mov 16(%edi), %ebp mov 6(%edi), %bx
mov 20(%edi), %esi mov 8(%edi), %bp
mov 24(%edi), %edi mov 10(%edi), %si
mov 12(%edi), %di
// This instruction will get written at runtime // This instruction will get written at runtime
_bf_int: .byte 0xCD, 0 // INT imm8 _bf_int: .byte 0xCD, 0 // INT imm8
push $0 push $0
pushf pushf
push %edi push %di
mov 8+4(%ebp), %edi mov 8+4(%ebp), %edi
mov %eax, 0(%edi) mov %ax, 0(%edi)
mov %ecx, 4(%edi) mov %cx, 2(%edi)
mov %edx, 8(%edi) mov %dx, 4(%edi)
mov %ebx, 12(%edi) mov %bx, 6(%edi)
mov %ebp, 16(%edi) mov %bp, 8(%edi)
mov %esi, 20(%edi) mov %si, 10(%edi)
pop %eax pop %ax
mov %eax, 24(%edi) mov %ax, 12(%edi)
PROT PROT
PROT32 PROT32
@ -123,6 +120,5 @@ _bf_int: .byte 0xCD, 0 // INT imm8
pop %edi pop %edi
pop %ebp pop %ebp
pop %ebx pop %ebx
mov %ebp, %esp leave
pop %ebp
ret ret

4
src/main.c
View file

@ -49,7 +49,7 @@ struct vesa_info {
uint8_t reserved[492]; uint8_t reserved[492];
}; };
extern uint16_t bios_func(uint8_t inum, uint32_t reg[]); extern uint16_t bios_func(uint8_t inum, uint16_t reg[]);
#define PG_PRESENT 0x001 #define PG_PRESENT 0x001
#define PG_WRITE 0x002 #define PG_WRITE 0x002
@ -123,7 +123,7 @@ main()
bios_write(buf); bios_write(buf);
#endif #endif
uint32_t reg[7]; uint16_t reg[7];
reg[0] = (0x0E << 8) + 'J'; reg[0] = (0x0E << 8) + 'J';
reg[1] = 0; reg[1] = 0;
reg[2] = 0; reg[2] = 0;