From 6121884d762e99668d74bad009bbad998ccfea45 Mon Sep 17 00:00:00 2001
From: Tom-on64 <kubecekt@gmail.com>
Date: Sat, 9 Mar 2024 20:52:22 +0100
Subject: [PATCH] Added ISRs for exceptions (taken from old-kern)

---
 src/kernel/entry.asm | 213 +++++++++++++++++++++++++++++++++++++++++++
 src/kernel/isrs.c    |  89 ++++++++++++++++++
 src/kernel/isrs.h    |  48 ++++++++++
 src/kernel/main.c    |   3 +-
 src/kernel/screen.c  |  10 ++
 src/kernel/screen.h  |   1 +
 src/kernel/system.c  |  12 +++
 src/kernel/system.h  |  10 +-
 8 files changed, 379 insertions(+), 7 deletions(-)
 create mode 100644 src/kernel/isrs.c
 create mode 100644 src/kernel/isrs.h

diff --git a/src/kernel/entry.asm b/src/kernel/entry.asm
index 46e2283..72211fd 100644
--- a/src/kernel/entry.asm
+++ b/src/kernel/entry.asm
@@ -3,6 +3,7 @@
 
 [extern main]
 [extern idtp]
+[extern faultHandler]
 
 _start:
     call main
@@ -13,3 +14,215 @@ _start:
 idtLoad:
     lidt [idtp]
     ret
+
+[global isr0]
+isr0:
+    cli
+    push 0
+    push 0
+    jmp isrCommon
+[global isr1]
+isr1:
+    cli
+    push 0
+    push 1
+    jmp isrCommon
+[global isr2]
+isr2:
+    cli
+    push 0
+    push 2
+    jmp isrCommon
+[global isr3]
+isr3:
+    cli
+    push 0
+    push 3
+    jmp isrCommon
+[global isr4]
+isr4:
+    cli
+    push 0
+    push 4
+    jmp isrCommon
+[global isr5]
+isr5:
+    cli
+    push 0
+    push 5
+    jmp isrCommon
+[global isr6]
+isr6:
+    cli
+    push 0
+    push 6
+    jmp isrCommon
+[global isr7]
+isr7:
+    cli
+    push 0
+    push 7
+    jmp isrCommon
+[global isr8]
+isr8:
+    cli
+    push 8
+    jmp isrCommon
+[global isr9]
+isr9:
+    cli
+    push 0
+    push 9
+    jmp isrCommon
+[global isr10]
+isr10:
+    cli
+    push 10
+    jmp isrCommon
+[global isr11]
+isr11:
+    cli
+    push 11
+    jmp isrCommon
+[global isr12]
+isr12:
+    cli
+    push 12
+    jmp isrCommon
+[global isr13]
+isr13:
+    cli
+    push 13
+    jmp isrCommon
+[global isr14]
+isr14:
+    cli
+    push 14
+    jmp isrCommon
+[global isr15]
+isr15:
+    cli
+    push 0
+    push 15
+    jmp isrCommon
+[global isr16]
+isr16:
+    cli
+    push 0
+    push 16
+    jmp isrCommon
+[global isr17]
+isr17:
+    cli
+    push 0
+    push 17
+    jmp isrCommon
+[global isr18]
+isr18:
+    cli
+    push 0
+    push 18
+    jmp isrCommon
+[global isr19]
+isr19:
+    cli
+    push 0
+    push 19
+    jmp isrCommon
+[global isr20]
+isr20:
+    cli
+    push 0
+    push 20
+    jmp isrCommon
+[global isr21]
+isr21:
+    cli
+    push 0
+    push 21
+    jmp isrCommon
+[global isr22]
+isr22:
+    cli
+    push 0
+    push 22
+    jmp isrCommon
+[global isr23]
+isr23:
+    cli
+    push 0
+    push 23
+    jmp isrCommon
+[global isr24]
+isr24:
+    cli
+    push 0
+    push 24
+    jmp isrCommon
+[global isr25]
+isr25:
+    cli
+    push 0
+    push 25
+    jmp isrCommon
+[global isr26]
+isr26:
+    cli
+    push 0
+    push 26
+    jmp isrCommon
+[global isr27]
+isr27:
+    cli
+    push 0
+    push 27
+    jmp isrCommon
+[global isr28]
+isr28:
+    cli
+    push 0
+    push 28
+    jmp isrCommon
+[global isr29]
+isr29:
+    cli
+    push 0
+    push 29
+    jmp isrCommon
+[global isr30]
+isr30:
+    cli
+    push 0
+    push 30
+    jmp isrCommon
+[global isr31]
+isr31:
+    cli
+    push 0
+    push 31
+    jmp isrCommon
+
+isrCommon:      ; No clue how this works, i'm pretty sure it calls the C function and has to push the registers or something idk
+    pusha
+    push ds
+    push es
+    push fs
+    push gs
+    mov ax, 0x10
+    mov ds, ax
+    mov es, ax
+    mov fs, ax
+    mov gs, ax
+    mov eax, esp
+    push eax
+    mov eax, faultHandler
+    call eax
+    pop eax
+    pop gs
+    pop fs
+    pop es
+    pop ds
+    popa
+    add esp, 8
+    iret
+
diff --git a/src/kernel/isrs.c b/src/kernel/isrs.c
new file mode 100644
index 0000000..9b252dc
--- /dev/null
+++ b/src/kernel/isrs.c
@@ -0,0 +1,89 @@
+#include "isrs.h"
+#include "idt.h"
+#include "screen.h"
+#include "system.h"
+
+char* exceptionMessages[] = {
+    "Divide By Zero Error",
+    "Debug Exception",
+    "NMI Interrupt",
+    "Breakpoint",
+    "Overflow",
+    "BOUND Range Exceeded",
+    "Invalid Opcode",
+    "Device Not Available",
+    "Double Fault",
+    "Coprocessor Segment Overrun",
+    "Invalid TSS",
+    "Segment Not Present",
+    "Stack-Segment Fault",
+    "General Protection Fault",
+    "Page Fault",
+    "Reserved",
+    "x87 FPU Floating-Point Error",
+    "Alignment Check",
+    "Machine Check",
+    "Reserved",
+    "Reserved",
+    "Reserved",
+    "Reserved",
+    "Reserved",
+    "Reserved",
+    "Reserved",
+    "Reserved",
+    "Reserved",
+    "Reserved",
+    "Reserved",
+    "Reserved",
+    "Reserved",
+};
+
+void setupIsrs() {
+    idtSetGate(0, (unsigned)isr0, 0x08, 0x8e);
+    idtSetGate(1, (unsigned)isr1, 0x08, 0x8e);
+    idtSetGate(2, (unsigned)isr2, 0x08, 0x8e);
+    idtSetGate(3, (unsigned)isr3, 0x08, 0x8e);
+    idtSetGate(4, (unsigned)isr4, 0x08, 0x8e);
+    idtSetGate(5, (unsigned)isr5, 0x08, 0x8e);
+    idtSetGate(6, (unsigned)isr6, 0x08, 0x8e);
+    idtSetGate(7, (unsigned)isr7, 0x08, 0x8e);
+    idtSetGate(8, (unsigned)isr8, 0x08, 0x8e);
+    idtSetGate(9, (unsigned)isr9, 0x08, 0x8e);
+    idtSetGate(10, (unsigned)isr10, 0x08, 0x8e);
+    idtSetGate(11, (unsigned)isr11, 0x08, 0x8e);
+    idtSetGate(12, (unsigned)isr12, 0x08, 0x8e);
+    idtSetGate(13, (unsigned)isr13, 0x08, 0x8e);
+    idtSetGate(14, (unsigned)isr14, 0x08, 0x8e);
+    idtSetGate(15, (unsigned)isr15, 0x08, 0x8e);
+    idtSetGate(16, (unsigned)isr16, 0x08, 0x8e);
+    idtSetGate(17, (unsigned)isr17, 0x08, 0x8e);
+    idtSetGate(18, (unsigned)isr18, 0x08, 0x8e);
+    idtSetGate(19, (unsigned)isr19, 0x08, 0x8e);
+    idtSetGate(20, (unsigned)isr20, 0x08, 0x8e);
+    idtSetGate(21, (unsigned)isr21, 0x08, 0x8e);
+    idtSetGate(22, (unsigned)isr22, 0x08, 0x8e);
+    idtSetGate(23, (unsigned)isr23, 0x08, 0x8e);
+    idtSetGate(24, (unsigned)isr24, 0x08, 0x8e);
+    idtSetGate(25, (unsigned)isr25, 0x08, 0x8e);
+    idtSetGate(26, (unsigned)isr26, 0x08, 0x8e);
+    idtSetGate(27, (unsigned)isr27, 0x08, 0x8e);
+    idtSetGate(28, (unsigned)isr28, 0x08, 0x8e);
+    idtSetGate(29, (unsigned)isr29, 0x08, 0x8e);
+    idtSetGate(30, (unsigned)isr30, 0x08, 0x8e);
+    idtSetGate(31, (unsigned)isr31, 0x08, 0x8e);
+}
+
+void faultHandler(struct regs* r) {
+    if (r->intNo < 32) {
+        print(exceptionMessages[r->intNo], 0x04);
+
+        if (r->errCode) { 
+            print(": 0x", 0x04);
+            printHex(r->errCode, 0x04);
+        }
+
+        cli();
+        hlt();
+    } 
+}
+
diff --git a/src/kernel/isrs.h b/src/kernel/isrs.h
new file mode 100644
index 0000000..50f7368
--- /dev/null
+++ b/src/kernel/isrs.h
@@ -0,0 +1,48 @@
+#ifndef ISRS_H
+#define ISRS_H
+
+void setupIsrs();
+
+// Contains values of registers and exception info from isrs
+struct regs {
+    unsigned int gs, fs, es, ds;
+    unsigned int edi, esi, ebp, esp, ebx, edx, ecx, eax;
+    unsigned int intNo, errCode;
+    unsigned int eip, cs, eflags, useresp, ss;
+};
+
+// Repetative isr definitions
+extern void isr0();
+extern void isr1();
+extern void isr2();
+extern void isr3();
+extern void isr4();
+extern void isr5();
+extern void isr6();
+extern void isr7();
+extern void isr8();
+extern void isr9();
+extern void isr10();
+extern void isr11();
+extern void isr12();
+extern void isr13();
+extern void isr14();
+extern void isr15();
+extern void isr16();
+extern void isr17();
+extern void isr18();
+extern void isr19();
+extern void isr20();
+extern void isr21();
+extern void isr22();
+extern void isr23();
+extern void isr24();
+extern void isr25();
+extern void isr26();
+extern void isr27();
+extern void isr28();
+extern void isr29();
+extern void isr30();
+extern void isr31();
+
+#endif
diff --git a/src/kernel/main.c b/src/kernel/main.c
index 9569bab..20fb4a8 100644
--- a/src/kernel/main.c
+++ b/src/kernel/main.c
@@ -1,11 +1,12 @@
 #include "screen.h"
 #include "idt.h"
+#include "isrs.h"
 
 void main() {
     setupIdt();
+    setupIsrs();
     clear(0x0f);
 
     print("kern.\n\n", 0x0f);
-    print("> ", 0x0e);
 }
 
diff --git a/src/kernel/screen.c b/src/kernel/screen.c
index 526a217..c24c9e9 100644
--- a/src/kernel/screen.c
+++ b/src/kernel/screen.c
@@ -50,6 +50,16 @@ void clear(uint8_t attr) {
     }
 }
 
+void printHex(uint8_t d, uint8_t attr) {
+    char digits[16] = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f' };
+    
+    uint8_t low = d & 0x0f;
+    uint8_t high = (d & 0xf0) >> 4;
+
+    putc(digits[low], attr);
+    putc(digits[high], attr);
+}
+
 void setCursorPos(uint16_t offset) {
     cursor = offset;
 }
diff --git a/src/kernel/screen.h b/src/kernel/screen.h
index ff19157..1751cb6 100644
--- a/src/kernel/screen.h
+++ b/src/kernel/screen.h
@@ -21,6 +21,7 @@ void print(char* s, uint8_t attr);
 void putcAt(char c, uint8_t attr, uint8_t row, uint8_t col);
 void printAt(char* s, uint8_t attr, uint8_t row, uint8_t col);
 void clear(uint8_t attr);
+void printHex(uint8_t d, uint8_t attr);
 
 void setCursorPos(uint16_t offset);
 uint16_t getCursorPos();
diff --git a/src/kernel/system.c b/src/kernel/system.c
index 78e1f69..46d3e2a 100644
--- a/src/kernel/system.c
+++ b/src/kernel/system.c
@@ -25,3 +25,15 @@ char* memset(char* dst, char value, uint16_t length) {
     return dst;
 }
 
+void cli() {
+    asm volatile("cli");
+}
+
+void sti() {
+    asm volatile("sti");
+}
+
+void hlt() {
+    asm volatile("hlt");
+}
+
diff --git a/src/kernel/system.h b/src/kernel/system.h
index c0311f8..4fddf9c 100644
--- a/src/kernel/system.h
+++ b/src/kernel/system.h
@@ -11,11 +11,9 @@ void outb(uint16_t port, uint8_t data);
 char* memcopy(char* src, char* dst, uint16_t length);
 char* memset(char* dst, char data, uint16_t length);
 
-struct regs {
-    unsigned int gs, fs, es, ds;
-    unsigned int edi, esi, ebp, esp, ebx, edx, ecx, eax;
-    unsigned int intNo, errCode;
-    unsigned int eip, cs, eflags, useresp, ss;
-};
+// Assembly stuff
+void cli();
+void sti();
+void hlt();
 
 #endif