From: John Tsiombikas <nuclear@member.fsf.org>
Date: Sun, 13 Oct 2019 14:46:38 +0000 (+0300)
Subject: fixed the interrupt gate descriptor setup
X-Git-Url: http://git.mutantstargoat.com/user/nuclear/?p=ld45_start_nothing;a=commitdiff_plain;h=74628dd7656a232ac4a701079fd81a742600985e

fixed the interrupt gate descriptor setup
---

diff --git a/src/boot/boot2.asm b/src/boot/boot2.asm
index 40807ef..df2653c 100644
--- a/src/boot/boot2.asm
+++ b/src/boot/boot2.asm
@@ -63,7 +63,7 @@ gdt_lim: dw 23
 gdt_base: dd gdt
 
 	align 4
-idt_lim: dw 111
+idt_lim: dw 2047
 idt_base: dd idt
 
 	align 8
@@ -85,6 +85,7 @@ idt:	times 104 db 0
 	dw 8
 	dw 8f00h    ; type: trap, present, default
 	dw 0
+	times 1944 db 0	; enough space for 256 gates
 
 gpf_msg: db "GP fault "
 
diff --git a/src/intr.asm b/src/intr.asm
index 58ef37f..fdd06ef 100644
--- a/src/intr.asm
+++ b/src/intr.asm
@@ -12,8 +12,81 @@ GATE_PRESENT equ 8000h
 	global init_intr
 init_intr:
 	call init_pic
+	; install trap handlers
+	set_trap 0, trap_entry_div
+	set_trap 1, trap_entry_debug
+	set_trap 2, trap_entry_nmi
+	set_trap 3, trap_entry_bp
+	set_trap 4, trap_entry_overflow
+	set_trap 5, trap_entry_bound
+	set_trap 6, trap_entry_ill
+	set_trap 7, trap_entry_nodev
+	set_trap 8, trap_entry_dfault
+	set_trap 9, trap_entry_copseg
+	set_trap 10, trap_entry_tss
+	set_trap 11, trap_entry_segpres
+	set_trap 12, trap_entry_stack
+	set_trap 13, trap_entry_prot
+	set_trap 14, trap_entry_page
+	set_trap 15, trap_entry_reserved
+	set_trap 16, trap_entry_fpu
+	set_trap 17, trap_entry_align
+	set_trap 18, trap_entry_mce
+	set_trap 19, trap_entry_sse
+
+	; 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
 	ret
 
+%macro trap_err 2
+	global trap_entry_%2
+trap_entry_%2:
+	push dword %1
+	jmp trap_entry_common
+%endmacro
+
+%macro trap_noerr 2
+	global trap_entry_%2
+trap_entry_%2:
+	push dword 0
+	push dword %1
+	jmp trap_entry_common
+%endmacro
+
+trap_entry_common:
+	pusha
+	; do exception handling
+	popa
+	add esp, 8	; remove error code and exception number from stack
+	iret
+	
+	trap_noerr 0, div
+	trap_noerr 1, debug
+	trap_noerr 2, nmi
+	trap_noerr 3, bp
+	trap_noerr 4, overflow
+	trap_noerr 5, bound
+	trap_noerr 6, ill
+	trap_noerr 7, nodev
+	trap_err 8, dfault
+	trap_noerr 9, copseg
+	trap_err 10, tss
+	trap_err 11, segpres
+	trap_err 12, stack
+	trap_err 13, prot
+	trap_err 14, page
+	trap_noerr 15, reserved
+	trap_noerr 16, fpu
+	trap_err 17, align
+	trap_noerr 18, mce
+	trap_noerr 19, sse
+
+
 	global set_intr
 set_intr:
 	push ebp
@@ -21,47 +94,38 @@ set_intr:
 	push ebx
 
 	mov ebx, [ebp + 8]
-	mov eax, GATE_TRAP
+	mov ax, GATE_TRAP
 	cmp ebx, 32	; determine if it's an IRQ or an exception (trap)
 	jb .notirq
-	mov eax, GATE_INTR
+	mov ax, 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
+	; type|dpl goes to the 3rd word of the descriptor (dpl is 0)
+	or ax, (GATE_DEFAULT | GATE_PRESENT)
+	mov [ebx + 4], ax
+	; address low 16bits go to the first word of the descriptor
 	mov eax, [ebp + 12]
 	mov [ebx], ax
-	; address high 16bits go to the last dword of the descriptor
+	; address high 16bits go to the last word 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
+	mov [ebx + 6], ax
+	; selector (kcode:1) goes to the second word of the descriptor
+	mov word [ebx + 2], 08h
 
 	pop ebx
 	pop ebp
 	ret
 
 dummy_intr_pic1:
-	push eax
+	pusha
 	end_of_irq 0
-	pop eax
+	popa
 	iret
 
 dummy_intr_pic2:
-	push eax
+	pusha
 	end_of_irq 8
-	pop eax
+	popa
 	iret
 
 ; PIC initialization command word 1 bits
diff --git a/src/intr.inc b/src/intr.inc
index a96b164..4bcc085 100644
--- a/src/intr.inc
+++ b/src/intr.inc
@@ -10,6 +10,12 @@ IRQ_OFFSET	equ 32
 %define IRQ_TO_INTR(x)	((x) + IRQ_OFFSET)
 %define INTR_TO_IRQ(x)	((x) - IRQ_OFFSET)
 
+%macro set_trap 2
+	push dword %2
+	push dword %1
+	call set_intr
+	add esp, 8
+%endmacro
 
 %macro set_irq_vector 2
 	push dword %2