LDH A,(C) and LDH (C), A
authorJoshua Wise <joshua@rebirth.joshuawise.com>
Sun, 30 Mar 2008 07:06:08 +0000 (03:06 -0400)
committerJoshua Wise <joshua@rebirth.joshuawise.com>
Sun, 30 Mar 2008 07:06:08 +0000 (03:06 -0400)
FPGABoy.ise
GBZ80Core.v
rom.hex

index fe38e42..d632f1e 100644 (file)
Binary files a/FPGABoy.ise and b/FPGABoy.ise differ
index 968cd26..1d06b12 100644 (file)
@@ -29,7 +29,8 @@
 `define INSN_LD_reg_imm16      8'b00xx0001
 `define INSN_LD_SP_HL          8'b11111001
 `define INSN_PUSH_reg          8'b11xx0101
-`define INSN_POP_reg           8'b11xx0001
+`define INSN_POP_reg                   8'b11xx0001
+`define INSN_LDH_AC                    8'b111x0010     // Either LDH A,(C) or LDH (C),A
 `define INSN_reg_A             3'b111
 `define INSN_reg_B             3'b000
 `define INSN_reg_C             3'b001
@@ -266,6 +267,23 @@ module GBZ80Core(
                                        end
                                endcase
                        end
+                       `INSN_LDH_AC: begin
+                               case (cycle)
+                               0:      begin
+                                               address <= {8'hFF,registers[`REG_C]};
+                                               if (opcode[4]) begin    // LD A,(C)
+                                                       rd <= 1;
+                                               end else begin
+                                                       wr <= 1;
+                                                       wdata <= {8'hFF,registers[`REG_A]};
+                                               end
+                                       end
+                               1: begin
+                                               `EXEC_NEWCYCLE;
+                                               `EXEC_INC_PC;
+                                       end
+                               endcase
+                       end
                        default:
                                $stop;
                        endcase
@@ -405,7 +423,17 @@ module GBZ80Core(
                                                cycle <= 0;
                                        end
                                endcase
-                       end     
+                       end
+                       `INSN_LDH_AC: begin
+                               case (cycle)
+                               0:      cycle <= 1;
+                               1: begin
+                                               cycle <= 0;
+                                               if (opcode[4])
+                                                       registers[`REG_A] <= rdata;
+                                       end
+                               endcase
+                       end
                        endcase
                        state <= `STATE_FETCH;
                end
diff --git a/rom.hex b/rom.hex
index 00214cd..c86844c 100644 (file)
--- a/rom.hex
+++ b/rom.hex
@@ -20,5 +20,5 @@ C1
 76
 
 @100
-00
+50
 56
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