From 79f04df82e9b756cadf667bc42f967132e113d64 Mon Sep 17 00:00:00 2001
From: Nathan Singer <nathan.r.singer@gmx.com>
Date: Thu, 5 Jun 2025 17:32:38 -0400
Subject: [PATCH] my exception handler sucked so i redid it

---
 Makefile                        |  2 +-
 kernel/arch/idt/idt.c           | 12 ++++---
 kernel/arch/idt/idt_src.s       | 60 ++++++++++++++++++++++++++-------
 kernel/include/kernel/x86/idt.h | 19 ++++++++++-
 4 files changed, 73 insertions(+), 20 deletions(-)

diff --git a/Makefile b/Makefile
index 04d77f2..0ceaa68 100644
--- a/Makefile
+++ b/Makefile
@@ -3,7 +3,7 @@
 
 CC = i686-elf-gcc
 
-DEBUG_FLAGS = -D__TESTING__ -g
+DEBUG_FLAGS = -D__TESTING__ -g -Wno-div-by-zero
 
 CFLAGS = -m32 -ffreestanding -Wall -Wextra -Werror -Wpedantic --sysroot=$(PWD)/sysroot -isystem=/usr/include -Iinclude -MD $(DEBUG_FLAGS)
 
diff --git a/kernel/arch/idt/idt.c b/kernel/arch/idt/idt.c
index 8e211bf..a688f3f 100644
--- a/kernel/arch/idt/idt.c
+++ b/kernel/arch/idt/idt.c
@@ -1,4 +1,5 @@
 #include <stdbool.h>
+#include <stdint.h>
 
 #ifdef __TESTING__
 #include <kernel/_kernel.h>
@@ -18,17 +19,18 @@ static bool vectors[IDT_MAX_DESCRIPTORS];
 
 extern struct keyboard_state keyb_state;
 
-void exception_handler(unsigned int i)
+void exception_handler(struct cpu_state __attribute__((unused)) cpu, uint32_t interrupt, struct stack_state stack)
 {
-	if (i <= 31) { // TODO: implement proper handling for each exception, also implement the proper gates & error code checking
+	printf("%1 %2\n", interrupt, stack.eflags);
+	if (interrupt <= 31) { // TODO: implement proper handling for each exception, also implement the proper gates & error code checking
 #ifdef __TESTING__
 		kerror("EXCEPTION");
-		printf("Exeption: %u\n", i);
+		printf("Exeption: %2\n", interrupt);
 #endif
-		__asm__ volatile ("cli; hlt"); // hangs the computer
+		//__asm__ volatile ("cli; hlt"); // hangs the computer
 	}
 
-	if (i == PIC_KEYB) {
+	if (interrupt == PIC_KEYB) {
 		unsigned char in = inb(0x60);
 		do_keypress(decode_scancode(in));
 		PIC_sendEOI(1);
diff --git a/kernel/arch/idt/idt_src.s b/kernel/arch/idt/idt_src.s
index b144030..469c920 100644
--- a/kernel/arch/idt/idt_src.s
+++ b/kernel/arch/idt/idt_src.s
@@ -1,27 +1,61 @@
 extern exception_handler
+extern exception_handler_err
 
 %macro isr_err_stub 1
 isr_stub_%+%1:
-	pushad
-	cld
-	push dword %1
-	call exception_handler
-	pop eax ; make sure to pop off the dword!!
-	popad
-	iret
+	;pushad
+	;cld
+	;push dword %1
+	;call exception_handler_err
+	;pop eax ; pop the error
+	;pop eax ; make sure to pop off the dword!!
+	;popad
+	;iret
+	push dword %1 ; push the interrupt number
+	jmp common_interrupt_handler
+
 %endmacro
 
 %macro isr_no_err_stub 1
 isr_stub_%+%1:
-	pushad
-	cld
+	;pushad
+	;cld
+	;push dword %1
+	;call exception_handler
+	;pop eax
+	;popad
+	;iret
+	push dword 0 
 	push dword %1
-	call exception_handler
-	pop eax
-	popad
-	iret
+	jmp common_interrupt_handler
 %endmacro
 
+common_interrupt_handler:
+	; lets save the registers
+	push eax
+	push ebx
+	push ecx
+	push edx
+	push esi
+	push edi
+	push ebp
+
+	call exception_handler
+
+	; restore the registers
+	pop ebp
+	pop edi
+	pop esi
+	pop edx
+	pop ecx
+	pop ebx
+	pop eax
+	
+	; restore the esp
+	add esp, 8
+
+	iret
+
 isr_no_err_stub 0
 isr_no_err_stub 1
 isr_no_err_stub 2
diff --git a/kernel/include/kernel/x86/idt.h b/kernel/include/kernel/x86/idt.h
index ed037e9..64e10e4 100644
--- a/kernel/include/kernel/x86/idt.h
+++ b/kernel/include/kernel/x86/idt.h
@@ -28,7 +28,24 @@
 #define EXCEPT_VIRT 20
 #define EXCEPT_CTRL_PROT 21
 
-void exception_handler(unsigned int i);
+struct cpu_state {
+	uint32_t eax;
+	uint32_t ebx;
+	uint32_t ecx;
+	uint32_t edx;
+	uint32_t esi;
+	uint32_t edi;
+	uint32_t ebp;
+} __attribute__((packed));
+
+struct stack_state {
+	uint32_t error_code;
+	uint32_t eip;
+	uint32_t cs;
+	uint32_t eflags;
+} __attribute__((packed));
+
+void exception_handler(struct cpu_state cpu, uint32_t interrupt, struct stack_state stack);
 
 typedef struct {
 	uint16_t isr_low;	// The lower 16 bits of the ISR's address