mmu_write_double, stack_push; LD (HL), n; JR; CALL

src/mmu.c

@@ -181,3 +181,13 @@ bool mmu_write_byte(MMU *mmu, uint16_t addr, uint8_t value)
         return true;
     }
 }
+
+/*
+    Write two bytes of memory to the given address.
+*/
+bool mmu_write_double(MMU *mmu, uint16_t addr, uint16_t value)
+{
+    bool b1 = mmu_write_byte(mmu, addr, value & 0xFF);
+    bool b2 = mmu_write_byte(mmu, addr + 1, value >> 8);
+    return b1 && b2;
+}

src/mmu.h

@@ -30,3 +30,4 @@ uint8_t mmu_read_byte(const MMU*, uint16_t);
 uint16_t mmu_read_double(const MMU*, uint16_t);
 uint32_t mmu_read_quad(const MMU*, uint16_t);
 bool mmu_write_byte(MMU*, uint16_t, uint8_t);
+bool mmu_write_double(MMU*, uint16_t, uint16_t);

src/z80.c

@@ -161,6 +161,15 @@ static inline void update_flags(Z80 *z80, bool c, bool n, bool pv, bool f3,
 }
 
 /*
+    Push a two-byte value onto the stack.
+*/
+static inline void stack_push(Z80 *z80, uint16_t value)
+{
+    z80->regfile.sp -= 2;
+    mmu_write_double(z80->mmu, z80->regfile.sp, value);
+}
+
+/*
     Read and return a byte from the given port.
 */
 static uint8_t read_port(Z80 *z80, uint8_t port)

src/z80_ops.inc.c

@@ -99,9 +99,18 @@ static uint8_t z80_inst_ld_r_hl(Z80 *z80, uint8_t opcode)
 // static uint8_t z80_inst_ld_iy_r(Z80 *z80, uint8_t opcode)
 
 /*
-    LD (HL), n
+    LD (HL), n (0x36):
+    Load n (8-bit immediate) into the memory address pointed to by HL.
 */
-// static uint8_t z80_inst_ld_hl_n(Z80 *z80, uint8_t opcode)
+static uint8_t z80_inst_ld_hl_n(Z80 *z80, uint8_t opcode)
+{
+    (void) opcode;
+    uint16_t addr = get_pair(z80, REG_HL);
+    uint8_t byte = mmu_read_byte(z80->mmu, ++z80->regfile.pc);
+    mmu_write_byte(z80->mmu, addr, byte);
+    z80->regfile.pc++;
+    return 10;
+}
 
 /*
     LD (IX+d), n
@@ -564,19 +573,38 @@ 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;
+        z80->regfile.pc += 3;
     return 10;
 }
 
-// JR e
-
-// JR C, e
-
-// JR NC, e
+/*
+    JR e (0x18):
+    Relative jump e (signed 8-bit immediate) bytes.
+*/
+static uint8_t z80_inst_jr_e(Z80 *z80, uint8_t opcode)
+{
+    (void) opcode;
+    int8_t jump = mmu_read_byte(z80->mmu, ++z80->regfile.pc);
+    z80->regfile.pc += jump + 2;
+    return 12;
+}
 
-// JR Z, e
 
-// JR NZ, e
+/*
+    JR cc, e (0x20, 0x28, 0x30, 0x38):
+    Relative jump e (signed 8-bit immediate) bytes if cc (condition) is true.
+*/
+static uint8_t z80_inst_jr_cc_e(Z80 *z80, uint8_t opcode)
+{
+    if (extract_cond(z80, opcode - 0x20)) {
+        int8_t jump = mmu_read_byte(z80->mmu, ++z80->regfile.pc);
+        z80->regfile.pc += jump + 2;
+        return 12;
+    } else {
+        z80->regfile.pc += 2;
+        return 7;
+    }
+}
 
 // JP (HL)
 
@@ -586,9 +614,33 @@ static uint8_t z80_inst_jp_cc_nn(Z80 *z80, uint8_t opcode)
 
 // DJNZ, e
 
-// CALL nn
+/*
+    CALL nn (0xCD):
+    Push PC+3 onto the stack and jump to nn (16-bit immediate).
+*/
+static uint8_t z80_inst_call_nn(Z80 *z80, uint8_t opcode)
+{
+    (void) opcode;
+    stack_push(z80, z80->regfile.pc + 3);
+    z80->regfile.pc = mmu_read_double(z80->mmu, ++z80->regfile.pc);
+    return 17;
+}
 
-// CALL cc, nn
+/*
+    CALL cc, nn (0xC4, 0xCC, 0xD4, 0xDC, 0xE4, 0xEC, 0xF4, 0xFC):
+    Push PC+3 onto the stack and jump to nn (16-bit immediate) if cc is true.
+*/
+static uint8_t z80_inst_call_cc_nn(Z80 *z80, uint8_t opcode)
+{
+    if (extract_cond(z80, opcode)) {
+        stack_push(z80, z80->regfile.pc + 3);
+        z80->regfile.pc = mmu_read_double(z80->mmu, ++z80->regfile.pc);
+        return 17;
+    } else {
+        z80->regfile.pc += 3;
+        return 10;
+    }
+}
 
 // RET
 

src/z80_tables.inc.c

@@ -26,7 +26,7 @@ static DispatchTable instruction_table = {
     [0x15] = z80_inst_unimplemented,  // TODO
     [0x16] = z80_inst_ld_r_n,
     [0x17] = z80_inst_unimplemented,  // TODO
-    [0x18] = z80_inst_unimplemented,  // TODO
+    [0x18] = z80_inst_jr_e,
     [0x19] = z80_inst_unimplemented,  // TODO
     [0x1A] = z80_inst_unimplemented,  // TODO
     [0x1B] = z80_inst_unimplemented,  // TODO
@@ -34,7 +34,7 @@ static DispatchTable instruction_table = {
     [0x1D] = z80_inst_unimplemented,  // TODO
     [0x1E] = z80_inst_ld_r_n,
     [0x1F] = z80_inst_unimplemented,  // TODO
-    [0x20] = z80_inst_unimplemented,  // TODO
+    [0x20] = z80_inst_jr_cc_e,
     [0x21] = z80_inst_ld_dd_nn,
     [0x22] = z80_inst_unimplemented,  // TODO
     [0x23] = z80_inst_inc_ss,
@@ -42,7 +42,7 @@ static DispatchTable instruction_table = {
     [0x25] = z80_inst_unimplemented,  // TODO
     [0x26] = z80_inst_ld_r_n,
     [0x27] = z80_inst_unimplemented,  // TODO
-    [0x28] = z80_inst_unimplemented,  // TODO
+    [0x28] = z80_inst_jr_cc_e,
     [0x29] = z80_inst_unimplemented,  // TODO
     [0x2A] = z80_inst_unimplemented,  // TODO
     [0x2B] = z80_inst_unimplemented,  // TODO
@@ -50,15 +50,15 @@ static DispatchTable instruction_table = {
     [0x2D] = z80_inst_unimplemented,  // TODO
     [0x2E] = z80_inst_ld_r_n,
     [0x2F] = z80_inst_unimplemented,  // TODO
-    [0x30] = z80_inst_unimplemented,  // TODO
+    [0x30] = z80_inst_jr_cc_e,
     [0x31] = z80_inst_ld_dd_nn,
     [0x32] = z80_inst_ld_nn_a,
     [0x33] = z80_inst_inc_ss,
     [0x34] = z80_inst_unimplemented,  // TODO
     [0x35] = z80_inst_unimplemented,  // TODO
-    [0x36] = z80_inst_unimplemented,  // TODO
+    [0x36] = z80_inst_ld_hl_n,
     [0x37] = z80_inst_unimplemented,  // TODO
-    [0x38] = z80_inst_unimplemented,  // TODO
+    [0x38] = z80_inst_jr_cc_e,
     [0x39] = z80_inst_unimplemented,  // TODO
     [0x3A] = z80_inst_unimplemented,  // TODO
     [0x3B] = z80_inst_unimplemented,  // TODO
@@ -198,7 +198,7 @@ static DispatchTable instruction_table = {
     [0xC1] = z80_inst_unimplemented,  // TODO
     [0xC2] = z80_inst_jp_cc_nn,
     [0xC3] = z80_inst_jp_nn,
-    [0xC4] = z80_inst_unimplemented,  // TODO
+    [0xC4] = z80_inst_call_cc_nn,
     [0xC5] = z80_inst_unimplemented,  // TODO
     [0xC6] = z80_inst_unimplemented,  // TODO
     [0xC7] = z80_inst_unimplemented,  // TODO
@@ -206,15 +206,15 @@ static DispatchTable instruction_table = {
     [0xC9] = z80_inst_unimplemented,  // TODO
     [0xCA] = z80_inst_jp_cc_nn,
     [0xCB] = z80_prefix_bits,
-    [0xCC] = z80_inst_unimplemented,  // TODO
-    [0xCD] = z80_inst_unimplemented,  // TODO
+    [0xCC] = z80_inst_call_cc_nn,
+    [0xCD] = z80_inst_call_nn,
     [0xCE] = z80_inst_unimplemented,  // TODO
     [0xCF] = z80_inst_unimplemented,  // TODO
     [0xD0] = z80_inst_unimplemented,  // TODO
     [0xD1] = z80_inst_unimplemented,  // TODO
     [0xD2] = z80_inst_jp_cc_nn,
     [0xD3] = z80_inst_out_n_a,
-    [0xD4] = z80_inst_unimplemented,  // TODO
+    [0xD4] = z80_inst_call_cc_nn,
     [0xD5] = z80_inst_unimplemented,  // TODO
     [0xD6] = z80_inst_unimplemented,  // TODO
     [0xD7] = z80_inst_unimplemented,  // TODO
@@ -222,7 +222,7 @@ static DispatchTable instruction_table = {
     [0xD9] = z80_inst_exx,
     [0xDA] = z80_inst_jp_cc_nn,
     [0xDB] = z80_inst_in_a_n,
-    [0xDC] = z80_inst_unimplemented,  // TODO
+    [0xDC] = z80_inst_call_cc_nn,
     [0xDD] = z80_prefix_index,
     [0xDE] = z80_inst_unimplemented,  // TODO
     [0xDF] = z80_inst_unimplemented,  // TODO
@@ -230,7 +230,7 @@ static DispatchTable instruction_table = {
     [0xE1] = z80_inst_unimplemented,  // TODO
     [0xE2] = z80_inst_jp_cc_nn,
     [0xE3] = z80_inst_unimplemented,  // TODO
-    [0xE4] = z80_inst_unimplemented,  // TODO
+    [0xE4] = z80_inst_call_cc_nn,
     [0xE5] = z80_inst_unimplemented,  // TODO
     [0xE6] = z80_inst_unimplemented,  // TODO
     [0xE7] = z80_inst_unimplemented,  // TODO
@@ -238,7 +238,7 @@ static DispatchTable instruction_table = {
     [0xE9] = z80_inst_unimplemented,  // TODO
     [0xEA] = z80_inst_jp_cc_nn,
     [0xEB] = z80_inst_unimplemented,  // TODO
-    [0xEC] = z80_inst_unimplemented,  // TODO
+    [0xEC] = z80_inst_call_cc_nn,
     [0xED] = z80_prefix_extended,
     [0xEE] = z80_inst_unimplemented,  // TODO
     [0xEF] = z80_inst_unimplemented,  // TODO
@@ -246,7 +246,7 @@ static DispatchTable instruction_table = {
     [0xF1] = z80_inst_unimplemented,  // TODO
     [0xF2] = z80_inst_jp_cc_nn,
     [0xF3] = z80_inst_di,
-    [0xF4] = z80_inst_unimplemented,  // TODO
+    [0xF4] = z80_inst_call_cc_nn,
     [0xF5] = z80_inst_unimplemented,  // TODO
     [0xF6] = z80_inst_unimplemented,  // TODO
     [0xF7] = z80_inst_unimplemented,  // TODO
@@ -254,7 +254,7 @@ static DispatchTable instruction_table = {
     [0xF9] = z80_inst_unimplemented,  // TODO
     [0xFA] = z80_inst_jp_cc_nn,
     [0xFB] = z80_inst_ei,
-    [0xFC] = z80_inst_unimplemented,  // TODO
+    [0xFC] = z80_inst_call_cc_nn,
     [0xFD] = z80_prefix_index,
     [0xFE] = z80_inst_cp_n,
     [0xFF] = z80_inst_unimplemented   // TODO