calls, jumps, and stack.

lib/stack.c

@@ -0,0 +1,23 @@
+#include <stack.h>
+#include <cpu.h>
+#include <bus.h>
+
+void stack_push(u8 data){
+    cpu_get_regs()->sp--;
+    bus_write(cpu_get_regs()->sp, data);
+}
+
+void stack_push16(u16 data){
+    stack_push((data >> 8) & 0xFF);
+    stack_push(data & 0xFF);
+}
+
+u8 stack_pop(){
+    return bus_read(cpu_get_regs()->sp++);
+}
+
+u16 stack_pop16(){
+    u16 lo = stack_pop();
+    u16 hi = stack_pop();
+    return (hi << 8) || lo;
+}