diff options
Diffstat (limited to 'stage2/main.asm')
| -rw-r--r-- | stage2/main.asm | 69 |
1 files changed, 65 insertions, 4 deletions
diff --git a/stage2/main.asm b/stage2/main.asm index 3cfb5d2..5027546 100644 --- a/stage2/main.asm +++ b/stage2/main.asm @@ -44,8 +44,69 @@ long_mode: mov gs, ax mov ss, ax - ; align stack - and rsp, ~(0x0f) - sub rsp, 8 + mov eax, [kernel_elf] + cmp eax, [.elf] + jne .fail - ; kernel begins here + mov r8, [kernel_elf+32] ; program header pos + add r8, kernel_elf + + movzx rbx, word[kernel_elf+54] ; program header size + movzx rdx, word[kernel_elf+56] ; num of program headers + +.header: + cmp rdx, 0 + je .start + + mov edi, [r8] ; type + cmp edi, 0 + je .next + + cmp edi, 1 + je .load + + cmp edi, 2 + je .fail + + cmp edi, 3 + je .fail + + jmp .next + +.load: + ; zero out the segment + mov al, 0 + mov rdi, [r8+16] + mov rcx, [r8+40] + rep stosb + + ; load from file + mov rdi, [r8+16] + mov rsi, [r8+8] + add rsi, kernel_elf + mov rcx, [r8+32] + rep movsb + +.next: + + add r8, rbx + dec rdx + jmp .header + +.start: + ; more stack space + mov rsp, 0x80000 + xor rbp, rbp + + ; ELF entry point + mov rax, [kernel_elf+24] + call rax + +.fail: + cli + hlt + jmp $ + +.elf: db 0x7f, "ELF" + +kernel_elf: |