X-Git-Url: http://git.mutantstargoat.com/user/nuclear/?p=ld45_start_nothing;a=blobdiff_plain;f=src%2Fintr.asm;h=58ef37fc344ddb9e5a2059784ad02dfd68944eac;hp=1bbf3197e6e470a5714485fa55c50665cc0d483c;hb=371bbe72cccdd5c40d5118bd0417fab062f3699a;hpb=6bbbb04131204b22367677209d7de8c3f906d0e2

diff --git a/src/intr.asm b/src/intr.asm
index 1bbf319..58ef37f 100644
--- a/src/intr.asm
+++ b/src/intr.asm
@@ -1,8 +1,14 @@
 ; vi:filetype=nasm ts=8 sts=8 sw=8:
 	section .text
 
+%define INTR_ASM_
 %include "intr.inc"
 
+GATE_INTR equ 0600h
+GATE_TRAP equ 0700h
+GATE_DEFAULT equ 0800h
+GATE_PRESENT equ 8000h
+
 	global init_intr
 init_intr:
 	call init_pic
@@ -10,12 +16,53 @@ init_intr:
 
 	global set_intr
 set_intr:
+	push ebp
+	mov ebp, esp
+	push ebx
+
+	mov ebx, [ebp + 8]
+	mov eax, GATE_TRAP
+	cmp ebx, 32	; determine if it's an IRQ or an exception (trap)
+	jb .notirq
+	mov eax, GATE_INTR
+.notirq:
+	shl ebx, 1
+	lea ebx, [ebx * 8 + idt] ; ebx <- pointer to gate descriptor
+	; type|dpl goes to the 3rd dword of the descriptor (dpl is 0)
+	or eax, (GATE_DEFAULT | GATE_PRESENT)
+	mov [ebx + 8], eax
+	; address low 16bits go to the first dword of the descriptor
+	mov eax, [ebp + 12]
+	mov [ebx], ax
+	; address high 16bits go to the last dword of the descriptor
+	shr eax, 16
+	mov [ebx + 12], eax
+	; selector (kcode:1) goes to the second dword of the descriptor
+	mov dword [ebx + 4], 08h
+
+	; install dummy interrupt handlers for all IRQ vectors
+%assign i 0
+%rep 8
+	set_irq_vector i, dummy_intr_pic1
+	set_irq_vector i+8, dummy_intr_pic2
+%assign i i+1
+%endrep
+
+	pop ebx
+	pop ebp
 	ret
 
-PIC1_CMD equ 20h
-PIC1_DATA equ 21h
-PIC2_CMD equ 0a0h
-PIC2_DATA equ 0a1h
+dummy_intr_pic1:
+	push eax
+	end_of_irq 0
+	pop eax
+	iret
+
+dummy_intr_pic2:
+	push eax
+	end_of_irq 8
+	pop eax
+	iret
 
 ; PIC initialization command word 1 bits
 ICW1_ICW4_NEEDED	equ 01h
@@ -29,8 +76,6 @@ ICW4_AUTO_EOI		equ 02h
 ICW4_BUF_SLAVE		equ 08h
 ICW4_BUF_MASTER		equ 0ch
 ICW4_SPECIAL		equ 10h
-; PIC operation command word 2 bits
-OCW2_EOI		equ 20h
 
 init_pic:
 	; send ICW1 saying we'll follow with ICW4 later on