Interrupt Descriptors implemented

Now just need to populate the IDT, then debug the whole thing.

include/interrupt_handlers.h

@@ -0,0 +1,14 @@
+#ifndef INTERRUPTHANDLERS_H
+#define INTERRUPTHANDLERS_H
+#include <stdint.h>
+extern void* isr_ptrs;
+
+typedef struct StateSnapshot_s {
+    uint32_t eax, ecx, edx, ebx, esp, esi, edi;
+    uint32_t interrupt_id, error_code;
+    uint32_t eip, cs, eflags;
+} StateSnapshot_t;
+
+void generic_isr_handler(StateSnapshot_t* cpu_state);
+
+#endif

src/allocidt.s

@@ -1,7 +1,9 @@
 global idtr, idt_start
 section .idtr
     idtr:
-        dw idt_end - idt_start
+        ;Normally, the size would be the size of the whole table, but i'm only defining 32 interrupts for now.
+        ;dw idt_end - idt_start
+        dw 32
         dd idt_start
 
 section .idt nobits

src/idt.c

@@ -0,0 +1,19 @@
+#include "idt.h"
+
+
+void setup_idt() {
+    write_descriptors();
+    load_idt();
+}
+
+void write_descriptors() {
+    
+    for(int i = 0; i < idtr.size; i+=(sizeof(InterruptDescriptor_t))) {
+             
+    }
+    return;
+}
+
+void load_idt() {
+    return;
+}

src/interrupt_handlers.c

@@ -0,0 +1,13 @@
+#include "interrupt_handlers.h"
+#include "kio.h"
+
+void generic_isr_handler(StateSnapshot_t* cpu_state) {
+    //We made it to C for our interrupt! For now, let's just print our interrupt to the screen.
+    vga_clear();
+    vga_printf("INTERRUPT TRIGGERED! Info below.\n");
+    vga_printf("Int_ID|ERR: %X|%X\n", cpu_state->interrupt_id, cpu_state->error_code);
+    vga_printf("EFLAGS|CS|EIP: %X|%X|%X\n", cpu_state->eflags, cpu_state->cs,cpu_state->eip);
+    vga_printf("GP Registers:\neax:%X\nebx:%X\necx:%X\nedx:%X\nesp:%X\nesi:%X\nedi:%X\n");
+    vga_printf("HALT!");
+    while(1);
+}

src/interrupts.s

@@ -2,11 +2,50 @@
 
 ;Let's make an interrupt pointer table so C can reference it and build the IDT. 
 
+global isr_ptrs
+extern generic_isr_handler
+
+;By the time we get here, we actually have a rather consistent stack:
+; dword [Interrupt ID]
+; dword [Error code (0 if int has no error code field)]
+; dword [EIP]
+; dword [CS]
+; dword [EFLAGS]
+; We can pass this to C. First, we might want to push all of our registers or something.
+isr_common:
+    pusha
+    push esp ;Throwing a pointer to ESP in there for referencing the aforementioned stuff as a struct
+    call generic_isr_handler
+    add esp,4 ;Remove that esp ref from the stack
+    popad ;restore our gp registers
+    add esp,4 ;deallocate the error code from the stack before heading out
+    iret
+
+%macro ISR_ENTRY 1
+isr_%1:
+    cli
+    %if %1 = 8 || %1 = 10 || %1 = 11 || %1 = 12 || %1 = 13 || %1 = 14 || %1 = 17 || %1 = 21
+    %else
+        push dword 0
+    %endif
+    push dword %1       ; saving our interrupt so C knows
+    jmp isr_common
+%endmacro
 
 
-isr_table:
+%assign j 0
+%rep 32
+    isr_ %+ j:
+       ISR_ENTRY j
+%assign j j+1
+%endrep
+; Generate a table of pointers that point to each of our ISRs. This will be accessed from C to setup our IDT.
+isr_ptrs:
     %assign i 0
-    %rep 21
+    %rep 32
-        isr_stub_ %+ i:
+        dd isr_ %+ i 
+    %assign i i+1
+    %endrep
+isr_ptrs_end: