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reorg boot.subx

This commit is contained in:
Kartik K. Agaram 2021-03-23 21:27:06 -07:00
parent 49a9938333
commit 7b89f8e67e
1 changed files with 9 additions and 10 deletions
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19
boot.subx
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@ -133,7 +133,7 @@
# 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 2/subop/lgdt 0/mod/indirect 6/rm32/use-disp16 0x7cf8/disp16/gdt_descriptor
0f 01 2/subop/lgdt 0/mod/indirect 6/rm32/use-disp16 0x7cf0/disp16/gdt_descriptor
# enable paging
0f 20/<-cr 3/mod/direct 0/rm32/eax 0/r32/cr0
66 83 1/subop/or 3/mod/direct 0/rm32/eax 1/imm8 # eax <- or 0x1
@ -180,11 +180,16 @@ gdt_start:
00 # base[24:32]
# gdt_end:
== data 0x7cf8
== data 0x7cf0
gdt_descriptor:
0x17/imm16 # final index of gdt = size of gdt - 1
gdt_start/imm32/start
== data 0x7cf8
idt_descriptor:
ff 03 # final index of idt = size of idt - 1
idt_start/imm32/start
## 32-bit code from this point
== code 0x7d00
@ -202,7 +207,7 @@ 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 3/subop/lidt 0/mod/indirect 5/rm32/use-disp32 0x8000/disp32/idt_descriptor
0f 01 3/subop/lidt 0/mod/indirect 5/rm32/use-disp32 0x7cf8/disp32/idt_descriptor
# For now, not bothering reprogramming the IRQ to not conflict with software
# exceptions.
@ -361,13 +366,7 @@ $keyboard-interrupt-handler:epilogue:
fb/enable-interrupts
cf/return-from-interrupt
## the rest of this file is all data
== data 0x8000
idt_descriptor:
ff 03 # final index of idt = size of idt - 1
idt_start/imm32/start
== data
Keyboard-shift-pressed?: # boolean
0/imm32