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1 files changed, 115 insertions, 0 deletions

diff --git a/src/int/pic.c b/src/int/pic.c
new file mode 100644
index 0000000..472e50c
--- /dev/null
+++ b/src/int/pic.c
@@ -0,0 +1,115 @@
+#include "pic.h"
+#include "utils/asm.h"
+#include "utils/mem.h"
+#include "utils/syscall.h"
+
+struct IDT_REGISTER IDTR={
+    200*8,
+    0x0
+};
+
+/// Bridge between IDT and functions call
+asm (
+".macro  SAVE_REGS        \n\t"
+    "pushal               \n\t"
+    "push %ds             \n\t"
+    "push %es             \n\t"
+    "push %fs             \n\t"
+    "push %gs             \n\t"
+    "push %ebx            \n\t"
+    "mov $0x10,%bx        \n\t"
+    "mov %bx,%ds          \n\t"
+    "pop %ebx             \n\t"
+".endm                    \n\t"
+".macro  RESTORE_REGS     \n\t"
+    "pop %gs              \n\t"
+    "pop %fs              \n\t"
+    "pop %es              \n\t"
+    "pop %ds              \n\t"
+    "popal                \n\t"
+".endm                    \n\t"
+"PIC_IRQ_DEFAULT:         \n\t"
+    "SAVE_REGS            \n\t"
+    "movb $0x20, %al      \n\t"
+    "outb %al, $0x20      \n\t"
+    "RESTORE_REGS         \n\t"
+    "iret                 \n\t"
+"PIC_IRQ_PRINT:           \n\t"
+    "SAVE_REGS            \n\t"
+    "call _8042_keypress  \n\t"
+    "movb $0x20, %al      \n\t"
+    "outb %al, $0x20      \n\t"
+    "RESTORE_REGS         \n\t"
+    "iret                 \n\t"
+"PIC_IRQ_CLOCK:           \n\t"
+    "SAVE_REGS            \n\t"
+    "call clock           \n\t"
+    "movb $0x20, %al      \n\t"
+    "outb %al, $0x20      \n\t"
+    "RESTORE_REGS         \n\t"
+    "iret                 \n\t"
+"PIC_IRQ_SYSCALL:         \n\t"
+    "SAVE_REGS            \n\t"
+    "call syscall         \n\t"
+    "movb $0x20, %al      \n\t"
+    "outb %al, $0x20      \n\t"
+    "RESTORE_REGS         \n\t"
+    "iret                 \n\t"
+"INT_PAGE_FAULT:          \n\t"
+    "SAVE_REGS            \n\t"
+    "call page_fault      \n\t"
+    "hlt                  \n\t"
+    "movb $0x20, %al      \n\t"
+    "outb %al, $0x20      \n\t"
+    "RESTORE_REGS         \n\t"
+    "iret                 \n\t"
+);
+
+extern u32 PIC_IRQ_DEFAULT,PIC_IRQ_PRINT,PIC_IRQ_CLOCK, PIC_IRQ_SYSCALL,INT_PAGE_FAULT;
+
+void pic_enable_interrupt(){
+    // Map first default 32 entries 
+    for(int i=0;i<200;i++){
+        pic_add_idt_entry((IDT_ENTRY){0x08,(u32)&PIC_IRQ_DEFAULT,IDT_INT_GATE},i);
+        if(i==14)
+            pic_add_idt_entry((IDT_ENTRY){0x08,(u32)&INT_PAGE_FAULT,IDT_INT_GATE},i);
+        if(i==32)
+            pic_add_idt_entry((IDT_ENTRY){0x08,(u32)&PIC_IRQ_CLOCK,IDT_INT_GATE},i);
+        if(i==33)
+            pic_add_idt_entry((IDT_ENTRY){0x08,(u32)&PIC_IRQ_PRINT,IDT_INT_GATE},i);
+        if(i==48)
+            pic_add_idt_entry((IDT_ENTRY){0x08,(u32)&PIC_IRQ_SYSCALL,IDT_TRAP_GATE},i);
+    }
+
+    // Now configure 8952A
+
+    // ICW1: Initialisation
+    outbj(0x20,0x11); // Master
+    outbj(0xA0,0x11); // Slave
+
+    // ICW2: Map IRQ index to entry into the IDT
+    outbj(0x21,0x20); // Start interrupt at offset 0x20 in IDT (index 32)
+    outbj(0xA1,0x70); // Start interrupt at offset 0x50 in IDT (index 80)
+
+    // ICW3: Indicate the connection between master and slave
+    outbj(0x21,0x02); // Slave connected to pin 2
+    outbj(0xA1,0x01); // Indicate pin id to the slave (2-1)
+
+    // ICW4: Operating mode
+    outbj(0x21,0x01); // Default operating mode
+    outbj(0xA1,0x01); // Default operating mode
+
+    // OCW: Masking
+    outbj(0x21,0b11111100);
+
+
+    asm("lidtl (IDTR)");
+    asm("sti");
+}
+
+void pic_add_idt_entry(IDT_ENTRY entry, int id){
+    int descriptor[2];
+    descriptor[0]=entry.offset & 0xFFFF | entry.segment << 16;
+    descriptor[1]=entry.type & 0xFFFF | entry.offset & 0xFFFF0000;
+    memcpy((void*)descriptor, (void *)(IDTR.base+(id*8)),8);
+}