Implement NEC V20/V30's i8080 emulation mode

src/cpu/i8080.h

@@ -0,0 +1,35 @@
+#ifndef I8080_I8080_H_
+#define I8080_I8080_H_
+
+#include <stdio.h>
+#include <stdint.h>
+#include <stdbool.h>
+
+typedef struct i8080 {
+  // memory + io interface
+  uint8_t (*read_byte)(void*, uint16_t); // user function to read from memory
+  void (*write_byte)(void*, uint16_t, uint8_t); // same for writing to memory
+  uint8_t (*read_byte_seg)(void*, uint16_t); // user function to read from memory (Code segment)
+  uint8_t (*port_in)(void*, uint8_t); // user function to read from port
+  void (*port_out)(void*, uint8_t, uint8_t); // same for writing to port
+  void* userdata; // user custom pointer
+
+  unsigned long cyc; // cycle count
+
+  uint16_t pc, sp; // program counter, stack pointer
+  uint8_t a, b, c, d, e, h, l; // registers
+  // flags: sign, zero, half-carry, parity, carry, interrupt flip-flop
+  bool sf : 1, zf : 1, hf : 1, pf : 1, cf : 1, iff : 1;
+  bool halted : 1;
+
+  bool interrupt_pending : 1;
+  uint8_t interrupt_vector;
+  uint8_t interrupt_delay;
+} i8080;
+
+void i8080_init(i8080* const c);
+void i8080_step(i8080* const c);
+void i8080_interrupt(i8080* const c, uint8_t opcode);
+void i8080_debug_output(i8080* const c, bool print_disassembly);
+
+#endif // I8080_I8080_H_