CP, IN, OUT, JP cc; stub out port functions.

src/z80.c

@@ -161,6 +161,28 @@ static inline void update_flags(Z80 *z80, bool c, bool n, bool pv, bool f3,
 }
 
 /*
+    Read and return a byte from the given port.
+*/
+static uint8_t read_port(Z80 *z80, uint8_t port)
+{
+    // TODO
+    (void) z80;
+    (void) port;
+    return 0x00;
+}
+
+/*
+    Write a byte to the given port.
+*/
+static void write_port(Z80 *z80, uint8_t port, uint8_t value)
+{
+    // TODO
+    (void) z80;
+    (void) port;
+    (void) value;
+}
+
+/*
     Extract an 8-bit register from the given opcode and return a pointer to it.
 */
 static inline uint8_t* extract_reg(Z80 *z80, uint8_t opcode)
@@ -192,6 +214,24 @@ static inline uint8_t extract_pair(uint8_t opcode)
 }
 
 /*
+    Extract a condition from the given opcode.
+*/
+static inline bool extract_cond(const Z80 *z80, uint8_t opcode)
+{
+    switch (opcode & 0x38) {
+        case 0x00: return !get_flag(z80, FLAG_ZERO);
+        case 0x08: return  get_flag(z80, FLAG_ZERO);
+        case 0x10: return !get_flag(z80, FLAG_CARRY);
+        case 0x18: return  get_flag(z80, FLAG_CARRY);
+        case 0x20: return !get_flag(z80, FLAG_PARITY);
+        case 0x28: return  get_flag(z80, FLAG_PARITY);
+        case 0x30: return !get_flag(z80, FLAG_SIGN);
+        case 0x38: return  get_flag(z80, FLAG_SIGN);
+    }
+    FATAL("invalid call: extract_cond(z80, 0x%02X)", opcode)
+}
+
+/*
     Return the CPU's current interrupt mode.
 */
 static inline uint8_t get_interrupt_mode(const Z80 *z80)

src/z80_ops.inc.c

@@ -312,6 +312,45 @@ static uint8_t z80_inst_xor_r(Z80 *z80, uint8_t opcode)
 // CP s
 
 /*
+    CP r (0xB8, 0xB9, 0xBA, 0xBB, 0xBC, 0xBD, 0xBF):
+    Set flags as if r (8-bit register) had been subtracted from a.
+*/
+static uint8_t z80_inst_cp_r(Z80 *z80, uint8_t opcode)
+{
+    uint8_t *reg = extract_reg(z80, opcode);
+    uint8_t d = z80->regfile.a - *reg;
+
+    bool c = (z80->regfile.a - *reg) != d;
+    bool v = (z80->regfile.a - *reg) != ((int8_t) d);
+    bool h = !!(((z80->regfile.a & 0x0F) - (*reg & 0x0F)) & 0x10);
+    update_flags(z80, c, 1, v, !!(*reg & 0x08), h, !!(*reg & 0x20), d == 0,
+                 !!(d & 0x80), 0xFF);
+
+    z80->regfile.pc++;
+    return 4;
+}
+
+/*
+    CP n (0xFE):
+    Set flags as if n (8-bit immediate) had been subtracted from a.
+*/
+static uint8_t z80_inst_cp_n(Z80 *z80, uint8_t opcode)
+{
+    (void) opcode;
+    uint8_t n = mmu_read_byte(z80->mmu, ++z80->regfile.pc);
+    uint8_t d = z80->regfile.a - n;
+
+    bool c = (z80->regfile.a - n) != d;
+    bool v = (z80->regfile.a - n) != ((int8_t) d);
+    bool h = !!(((z80->regfile.a & 0x0F) - (n & 0x0F)) & 0x10);
+    update_flags(z80, c, 1, v, !!(n & 0x08), h, !!(n & 0x20), d == 0,
+                 !!(d & 0x80), 0xFF);
+
+    z80->regfile.pc++;
+    return 7;
+}
+
+/*
     INC r (0x04, 0x0C, 0x14, 0x1C, 0x24, 0x2C, 0x3C):
     Increment r (8-bit register).
 */
@@ -516,7 +555,18 @@ static uint8_t z80_inst_jp_nn(Z80 *z80, uint8_t opcode)
     return 10;
 }
 
-// JP cc, nn
+/*
+    JP cc, nn (0xC2, 0xCA, 0xD2, 0xDA, 0xE2, 0xEA, 0xF2, 0xFA):
+    Jump to nn (16-bit immediate) if cc (condition) is true.
+*/
+static uint8_t z80_inst_jp_cc_nn(Z80 *z80, uint8_t opcode)
+{
+    if (extract_cond(z80, opcode))
+        z80->regfile.pc = mmu_read_double(z80->mmu, ++z80->regfile.pc);
+    else
+        z80->regfile.pc += 2;
+    return 10;
+}
 
 // JR e
 
@@ -550,7 +600,18 @@ static uint8_t z80_inst_jp_nn(Z80 *z80, uint8_t opcode)
 
 // RST p
 
-// IN A, (n)
+/*
+    IN A, (n): (0xDB):
+    Read a byte from port n into a.
+*/
+static uint8_t z80_inst_in_a_n(Z80 *z80, uint8_t opcode)
+{
+    (void) opcode;
+    uint8_t port = mmu_read_byte(z80->mmu, ++z80->regfile.pc);
+    z80->regfile.a = read_port(z80, port);
+    z80->regfile.pc++;
+    return 11;
+}
 
 // IN r (C)
 
@@ -562,7 +623,18 @@ static uint8_t z80_inst_jp_nn(Z80 *z80, uint8_t opcode)
 
 // INDR
 
-// OUT (n), A
+/*
+    OUT (n), A: (0xD3):
+    Write a byte from a into port n.
+*/
+static uint8_t z80_inst_out_n_a(Z80 *z80, uint8_t opcode)
+{
+    (void) opcode;
+    uint8_t port = mmu_read_byte(z80->mmu, ++z80->regfile.pc);
+    write_port(z80, port, z80->regfile.a);
+    z80->regfile.pc++;
+    return 11;
+}
 
 // OUT (C), r
 

src/z80_tables.inc.c

@@ -186,17 +186,17 @@ static DispatchTable instruction_table = {
     [0xB5] = z80_inst_unimplemented,  // TODO
     [0xB6] = z80_inst_unimplemented,  // TODO
     [0xB7] = z80_inst_unimplemented,  // TODO
-    [0xB8] = z80_inst_unimplemented,  // TODO
-    [0xB9] = z80_inst_unimplemented,  // TODO
-    [0xBA] = z80_inst_unimplemented,  // TODO
-    [0xBB] = z80_inst_unimplemented,  // TODO
-    [0xBC] = z80_inst_unimplemented,  // TODO
-    [0xBD] = z80_inst_unimplemented,  // TODO
+    [0xB8] = z80_inst_cp_r,
+    [0xB9] = z80_inst_cp_r,
+    [0xBA] = z80_inst_cp_r,
+    [0xBB] = z80_inst_cp_r,
+    [0xBC] = z80_inst_cp_r,
+    [0xBD] = z80_inst_cp_r,
     [0xBE] = z80_inst_unimplemented,  // TODO
-    [0xBF] = z80_inst_unimplemented,  // TODO
+    [0xBF] = z80_inst_cp_r,
     [0xC0] = z80_inst_unimplemented,  // TODO
     [0xC1] = z80_inst_unimplemented,  // TODO
-    [0xC2] = z80_inst_unimplemented,  // TODO
+    [0xC2] = z80_inst_jp_cc_nn,
     [0xC3] = z80_inst_jp_nn,
     [0xC4] = z80_inst_unimplemented,  // TODO
     [0xC5] = z80_inst_unimplemented,  // TODO
@@ -204,7 +204,7 @@ static DispatchTable instruction_table = {
     [0xC7] = z80_inst_unimplemented,  // TODO
     [0xC8] = z80_inst_unimplemented,  // TODO
     [0xC9] = z80_inst_unimplemented,  // TODO
-    [0xCA] = z80_inst_unimplemented,  // TODO
+    [0xCA] = z80_inst_jp_cc_nn,
     [0xCB] = z80_prefix_bits,
     [0xCC] = z80_inst_unimplemented,  // TODO
     [0xCD] = z80_inst_unimplemented,  // TODO
@@ -212,23 +212,23 @@ static DispatchTable instruction_table = {
     [0xCF] = z80_inst_unimplemented,  // TODO
     [0xD0] = z80_inst_unimplemented,  // TODO
     [0xD1] = z80_inst_unimplemented,  // TODO
-    [0xD2] = z80_inst_unimplemented,  // TODO
-    [0xD3] = z80_inst_unimplemented,  // TODO
+    [0xD2] = z80_inst_jp_cc_nn,
+    [0xD3] = z80_inst_out_n_a,
     [0xD4] = z80_inst_unimplemented,  // TODO
     [0xD5] = z80_inst_unimplemented,  // TODO
     [0xD6] = z80_inst_unimplemented,  // TODO
     [0xD7] = z80_inst_unimplemented,  // TODO
     [0xD8] = z80_inst_unimplemented,  // TODO
     [0xD9] = z80_inst_exx,
-    [0xDA] = z80_inst_unimplemented,  // TODO
-    [0xDB] = z80_inst_unimplemented,  // TODO
+    [0xDA] = z80_inst_jp_cc_nn,
+    [0xDB] = z80_inst_in_a_n,
     [0xDC] = z80_inst_unimplemented,  // TODO
     [0xDD] = z80_prefix_index,
     [0xDE] = z80_inst_unimplemented,  // TODO
     [0xDF] = z80_inst_unimplemented,  // TODO
     [0xE0] = z80_inst_unimplemented,  // TODO
     [0xE1] = z80_inst_unimplemented,  // TODO
-    [0xE2] = z80_inst_unimplemented,  // TODO
+    [0xE2] = z80_inst_jp_cc_nn,
     [0xE3] = z80_inst_unimplemented,  // TODO
     [0xE4] = z80_inst_unimplemented,  // TODO
     [0xE5] = z80_inst_unimplemented,  // TODO
@@ -236,7 +236,7 @@ static DispatchTable instruction_table = {
     [0xE7] = z80_inst_unimplemented,  // TODO
     [0xE8] = z80_inst_unimplemented,  // TODO
     [0xE9] = z80_inst_unimplemented,  // TODO
-    [0xEA] = z80_inst_unimplemented,  // TODO
+    [0xEA] = z80_inst_jp_cc_nn,
     [0xEB] = z80_inst_unimplemented,  // TODO
     [0xEC] = z80_inst_unimplemented,  // TODO
     [0xED] = z80_prefix_extended,
@@ -244,7 +244,7 @@ static DispatchTable instruction_table = {
     [0xEF] = z80_inst_unimplemented,  // TODO
     [0xF0] = z80_inst_unimplemented,  // TODO
     [0xF1] = z80_inst_unimplemented,  // TODO
-    [0xF2] = z80_inst_unimplemented,  // TODO
+    [0xF2] = z80_inst_jp_cc_nn,
     [0xF3] = z80_inst_di,
     [0xF4] = z80_inst_unimplemented,  // TODO
     [0xF5] = z80_inst_unimplemented,  // TODO
@@ -252,11 +252,11 @@ static DispatchTable instruction_table = {
     [0xF7] = z80_inst_unimplemented,  // TODO
     [0xF8] = z80_inst_unimplemented,  // TODO
     [0xF9] = z80_inst_unimplemented,  // TODO
-    [0xFA] = z80_inst_unimplemented,  // TODO
+    [0xFA] = z80_inst_jp_cc_nn,
     [0xFB] = z80_inst_ei,
     [0xFC] = z80_inst_unimplemented,  // TODO
     [0xFD] = z80_prefix_index,
-    [0xFE] = z80_inst_unimplemented,  // TODO
+    [0xFE] = z80_inst_cp_n,
     [0xFF] = z80_inst_unimplemented   // TODO
 };