isr: add keyboard (0x21) handler

Makefile

@@ -41,7 +41,7 @@ bin/screen.o: src/screen.c
 	$(CC) $(CFLAGS) -c $< -o $@
 
 bin/isr.o: src/isr.c
-	$(CC) $(CFLAGS) -c $< -o $@
+	$(CC) $(CFLAGS) -mgeneral-regs-only -c $< -o $@
 
 bin/idt.o: src/idt.c
 	$(CC) $(CFLAGS) -c $< -o $@

include/pic.h

@@ -4,5 +4,6 @@
 #include "../include/utils.h"
 
 void pic_remap(int offset1, int offset2);
+void pic_end_int(uint8_t irq);
 
 #endif

src/isr.c

@@ -2,6 +2,7 @@
 #include "../include/isr.h"
 #include "../include/types.h"
 #include "../include/screen.h"
+#include "../include/pic.h"
 
 void isr_custom();
 void default_handler();
@@ -55,10 +56,23 @@ void default_handler()
 
 }
 
-void isr_custom()
+
+#include <stddef.h>
+#include <stdint.h>
+typedef size_t uword_t;
+struct interrupt_frame
+{
+    uword_t ip;
+    uword_t cs;
+    uword_t flags;
+    uword_t sp;
+    uword_t ss;
+};
+
+__attribute__((interrupt)) void isr_custom(struct interrupt_frame *frame)
 {
 	terminal_writestring("YOOOOO!!!!!! I LOVE KATYA!!!!");
-	asm("hlt");
+	pic_end_int(0x21);
 }
 
 void isr0()

src/pic.c

@@ -70,3 +70,8 @@ void pic_disable(void) {
     outb(PIC1_DATA, 0xff);
     outb(PIC2_DATA, 0xff);
 }
+
+void pic_end_int(uint8_t irq) {
+  if (irq >= 8) outb(PIC2_COMMAND, 0x20);
+  outb(PIC1_COMMAND, 0x20);
+}