diff options
| -rw-r--r-- | boot.subx | 35 |
1 files changed, 14 insertions, 21 deletions
diff --git a/boot.subx b/boot.subx index d729f13e..4f6e485b 100644 --- a/boot.subx +++ b/boot.subx @@ -155,15 +155,15 @@ # We can't refer to the label directly because SubX doesn't do the right # thing for lgdt, so rather than make errors worse in most places we instead # pin gdt_descriptor below. - 0f 01/lgdt 0/mod/indirect 2/subop/lgdt 6/rm32/use-disp16 0x7cf8/disp16/gdt_descriptor + 0f 01/lgdt 2/subop/lgdt 0/mod/indirect 6/rm32/use-disp16 0x7cf8/disp16/gdt_descriptor # enable paging - 0f 20/cr-> 3/mod/direct 0/rm32/cr0 0/r32/eax + 0f 20/<-cr 3/mod/direct 0/rm32/eax 0/r32/cr0 == data # TODO: SubX doesn't understand 66 prefix #? 66 83/or 3/mod/direct 0/rm32/eax 1/r32/?? 1/imm8 # eax <- or 0x1 66 83 c8 01 # eax <- or 0x1 == code - 0f 22/cr<- 3/mod/direct 0/rm32/cr0 0/r32/eax + 0f 22/->cr 3/mod/direct 0/rm32/eax 0/r32/cr0 # far jump to initialize_32bit_mode that sets cs to offset 8 in the gdt in the process # We can't refer to the label directly because SubX doesn't have syntax for # segment selectors. So we instead pin initialize_32bit_mode below. @@ -242,9 +242,7 @@ initialize_32bit_mode: # We can't refer to the label directly because SubX doesn't do the right # thing for lidt, so rather than make errors worse in most places we instead # pin idt_descriptor below. - 0f 01/lidt 0/mod/indirect 3/subop/lidt 5/rm32/use-disp32 0x8000/disp32/idt_descriptor - -== data + 0f 01/lidt 3/subop/lidt 0/mod/indirect 5/rm32/use-disp32 0x8000/disp32/idt_descriptor # For now, not bothering reprogramming the IRQ to not conflict with software # exceptions. @@ -255,27 +253,22 @@ initialize_32bit_mode: # Reference: # https://wiki.osdev.org/Exceptions -# 11a: # enable keyboard IRQ (1) - b0 fd # al <- 0xfd # disable mask for IRQ1 - e6 21 # port 0x21 <- al + b0/copy-to-al 0xfd/imm8 # disable mask for IRQ1 + e6/write-al-into-port 0x21/imm8 -# 11e: - fb # enable interrupts - db e3 # initialize FPU + fb/enable-interrupts +== data + db e3/initialize-floating-point-coprocessor +== code # eax <- cr4 - 0f 20 # copy cr4 to rm32 - e0 # 11/mod/direct 100/r32/CR4 000/rm32/eax + 0f 20/<-cr 3/mod/direct 0/rm32/eax 4/r32/cr4 # eax <- or bit 9 - 0f ba - e8 # 11/mod/direct 101/subop/bit-test-and-set 000/rm32/eax - 09 # imm8 + 0f ba/bit-test 5/subop/bit-test-and-set 3/mod/direct 0/rm32/eax 9/imm8 # cr4 <- eax - 0f 22 # copy rm32 to cr4 - e0 # 11/mod/direct 100/r32/CR4 000/rm32/eax - e9 d0 16 00 00 # jump to 0x9400 [label] - + 0f 22/->cr 3/mod/direct 0/rm32/eax 4/r32/cr4 == data + e9 d0 16 00 00 # jump to 0x9400 [label] # padding # 130: |