X-Git-Url: http://git.joshuawise.com/fpgaboy.git/blobdiff_plain/6c46357c6f1bfeefc3a9f85aed03f94e923d09f1..c279b66691509cfc4445a568dab29a3282f03f3f:/GBZ80Core.v?ds=sidebyside

diff --git a/GBZ80Core.v b/GBZ80Core.v
index 36cd76a..45870d1 100644
--- a/GBZ80Core.v
+++ b/GBZ80Core.v
@@ -40,34 +40,45 @@
 `define STATE_EXECUTE		2'h2
 `define STATE_WRITEBACK		2'h3
 
-`define INSN_LD_reg_imm8	8'b00xxx110
-`define INSN_HALT		8'b01110110
-`define INSN_LD_HL_reg		8'b01110xxx
-`define INSN_LD_reg_HL		8'b01xxx110
-`define INSN_LD_reg_reg		8'b01xxxxxx
-`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_LDH_AC		8'b111x0010	// Either LDH A,(C) or LDH (C),A
-`define INSN_LDx_AHL		8'b001xx010	// LDD/LDI A,(HL) / (HL),A
-`define INSN_ALU8		8'b10xxxxxx	// 10 xxx yyy
-`define INSN_NOP		8'b00000000
-`define INSN_RST		8'b11xxx111
-`define INSN_RET		8'b110x1001	// 1 = RETI, 0 = RET
-`define INSN_RETCC		8'b110xx000
-`define INSN_CALL		8'b11001101
-`define INSN_CALLCC		8'b110xx100	// Not that call/cc.
-`define INSN_JP_imm		8'b11000011
-`define INSN_JPCC_imm		8'b110xx010
-`define INSN_ALU_A		8'b00xxx111
-`define INSN_JP_HL		8'b11101001
-`define INSN_JR_imm		8'b00011000
-`define INSN_JRCC_imm		8'b001xx000
-`define INSN_INCDEC16		8'b00xxx011
-`define INSN_VOP_INTR		8'b11111100	// 0xFC is grabbed by the fetch if there is an interrupt pending.
-`define INSN_DI			8'b11110011
-`define INSN_EI			8'b11111011
+`define INSN_LD_reg_imm8	9'b000xxx110
+`define INSN_HALT		9'b001110110
+`define INSN_LD_HL_reg		9'b001110xxx
+`define INSN_LD_reg_HL		9'b001xxx110
+`define INSN_LD_reg_reg		9'b001xxxxxx
+`define INSN_LD_reg_imm16	9'b000xx0001
+`define INSN_LD_SP_HL		9'b011111001
+`define INSN_PUSH_reg		9'b011xx0101
+`define INSN_POP_reg		9'b011xx0001
+`define INSN_LDH_AC		9'b0111x0010	// Either LDH A,(C) or LDH (C),A
+`define INSN_LDx_AHL		9'b0001xx010	// LDD/LDI A,(HL) / (HL),A
+`define INSN_ALU8		9'b010xxxxxx	// 10 xxx yyy
+`define INSN_ALU8IMM		9'b011xxx110
+`define INSN_NOP		9'b000000000
+`define INSN_RST		9'b011xxx111
+`define INSN_RET		9'b0110x1001	// 1 = RETI, 0 = RET
+`define INSN_RETCC		9'b0110xx000
+`define INSN_CALL		9'b011001101
+`define INSN_CALLCC		9'b0110xx100	// Not that call/cc.
+`define INSN_JP_imm		9'b011000011
+`define INSN_JPCC_imm		9'b0110xx010
+`define INSN_ALU_A		9'b000xxx111
+`define INSN_JP_HL		9'b011101001
+`define INSN_JR_imm		9'b000011000
+`define INSN_JRCC_imm		9'b0001xx000
+`define INSN_INCDEC16		9'b000xxx011
+`define INSN_VOP_INTR		9'b011111100	// 0xFC is grabbed by the fetch if there is an interrupt pending.
+`define INSN_DI			9'b011110011
+`define INSN_EI			9'b011111011
+`define INSN_INCDEC_HL		9'b00011010x
+`define INSN_INCDEC_reg8	9'b000xxx10x
+`define INSN_LD8M_A		9'b0111x0000	// 1111 for ld A, x; 1110 for ld x, A; bit 1 specifies 16m8 or 8m8
+`define INSN_LD16M_A		9'b0111x1010	// 1111 for ld A, x; 1110 for ld x, A; bit 1 specifies 16m8 or 8m8
+`define INSN_LDBCDE_A		9'b0000xx010
+`define INSN_TWO_BYTE		9'b011001011    // prefix for two-byte opqodes
+`define INSN_ALU_EXT		9'b100xxxxxx
+`define INSN_BIT		9'b101xxxxxx
+`define INSN_RES		9'b110xxxxxx
+`define INSN_SET		9'b111xxxxxx
 
 `define INSN_cc_NZ		2'b00
 `define INSN_cc_Z		2'b01
@@ -106,10 +117,19 @@
 `define INSN_alu_CPL		3'b101
 `define INSN_alu_SCF		3'b110
 `define INSN_alu_CCF		3'b111
+`define INSN_alu_RLC		3'b000
+`define INSN_alu_RRC		3'b001
+`define INSN_alu_RL		3'b010
+`define INSN_alu_RR		3'b011
+`define INSN_alu_DA_SLA		3'b100
+`define INSN_alu_CPL_SRA	3'b101
+`define INSN_alu_SCF_SWAP	3'b110
+`define INSN_alu_CCF_SRL	3'b111
 
 `define EXEC_INC_PC 		`_PC <= `_PC + 1;
 `define EXEC_NEXTADDR_PCINC	address <= `_PC + 1;
 `define EXEC_NEWCYCLE		begin newcycle <= 1; rd <= 1; wr <= 0; end
+`define EXEC_NEWCYCLE_TWOBYTE	begin newcycle <= 1; rd <= 1; wr <= 0; twobyte <= 1; end
 `define EXEC_WRITE(ad, da)	begin address <= (ad); wdata <= (da); wr <= 1; end end
 `define EXEC_READ(ad)		begin address <= (ad); rd <= 1; end end
 
@@ -120,7 +140,7 @@ module GBZ80Core(
 	output reg buswr, output reg busrd,
 	input irq, input [7:0] jaddr,
 	output reg [1:0] state);
-	
+
 //	reg [1:0] state;					/* State within this bus cycle (see STATE_*). */
 	reg [2:0] cycle;					/* Cycle for instructions. */
 	
@@ -128,18 +148,77 @@ module GBZ80Core(
 	
 	reg [15:0] address;				/* Address for the next bus operation. */
 	
-	reg [7:0] opcode;				/* Opcode from the current machine cycle. */
-	
+	reg [8:0] opcode;				/* Opcode from the current machine cycle. */
+
 	reg [7:0] rdata, wdata;		/* Read data from this bus cycle, or write data for the next. */
-	reg rd, wr, newcycle;
+	reg rd, wr, newcycle, twobyte;
 	
 	reg [7:0] tmp, tmp2;			/* Generic temporary regs. */
 	
 	reg [7:0] buswdata;
 	assign busdata = buswr ? buswdata : 8'bzzzzzzzz;
-	
+
 	reg ie, iedelay;
-	
+
+	wire [7:0] rlc,rrc,rl,rr,sla,sra,swap,srl;
+	wire [3:0] rlcf,rrcf,rlf,rrf,slaf,sraf,swapf,srlf;
+	wire [7:0] alu_res;
+	wire [3:0] f_res;
+
+	assign rlc   = {tmp[6:0],tmp[7]};
+	assign rlcf  = {(tmp == 0 ? 1'b1 : 1'b0)
+			,2'b0,
+			tmp[7]};
+
+	assign rrc   = {tmp[0],tmp[7:1]};
+	assign rrcf  = {(tmp == 0 ? 1'b1 : 1'b0),
+			2'b0,
+			tmp[0]};
+
+	assign rl    = {tmp[6:0],`_F[4]};
+	assign rlf   = {({tmp[6:0],`_F[4]} == 0 ? 1'b1 : 1'b0),
+			2'b0,
+			tmp[7]};
+
+	assign rr    = {`_F[4],tmp[7:1]};
+	assign rrf   = {({tmp[4],tmp[7:1]} == 0 ? 1'b1 : 1'b0),
+			2'b0,
+			tmp[0]};
+
+	assign sla   = {tmp[6:0],0};
+	assign slaf  = {(tmp[6:0] == 0 ? 1'b1 : 1'b0),
+			2'b0,
+			tmp[7]};
+
+	assign sra   = {tmp[7],tmp[7:1]};
+//	assign sraf  = {(tmp[7:1] == 0 ? 1'b1 : 1'b0),2'b0,tmp[0]};   now in assign srlf =
+
+	assign swap  = {tmp[3:0],tmp[7:4]};
+	assign swapf = {(tmp == 0 ? 1'b1 : 1'b0),
+			3'b0};
+
+	assign srl   = {0,tmp[7:1]};
+	assign srlf  = {(tmp[7:1] == 0 ? 1'b1 : 1'b0),
+			2'b0,
+			tmp[0]};
+	assign sraf  = srlf;
+
+	/*  Y U Q  */
+	assign {alu_res,f_res} =
+		opcode[5] ? (
+			opcode[4] ? (
+				opcode[3] ? {srl,srlf} : {swap,swapf}
+			) : (
+				opcode[3] ? {sra,sraf} : {sla,slaf}
+			)
+		) : (
+			opcode[4] ? (
+				opcode[3] ? {rr,rrf} : {rl,rlf}
+			) : (
+				opcode[3] ? {rrc,rrcf} : {rlc,rlcf}
+			)
+		);
+
 	initial begin
 		registers[ 0] <= 0;
 		registers[ 1] <= 0;
@@ -166,13 +245,14 @@ module GBZ80Core(
 		opcode <= 0;
 		state <= `STATE_WRITEBACK;
 		cycle <= 0;
+		twobyte <= 0;
 	end
 
 	always @(posedge clk)
 		case (state)
 		`STATE_FETCH: begin
 			if (newcycle) begin
-				busaddress <= {registers[`REG_PCH], registers[`REG_PCL]};
+				busaddress <= `_PC;
 				buswr <= 0;
 				busrd <= 1;
 			end else begin
@@ -186,10 +266,13 @@ module GBZ80Core(
 		end
 		`STATE_DECODE: begin
 			if (newcycle) begin
-				if (ie && irq)
+				if (twobyte) begin
+					opcode <= {1,busdata};
+					twobyte <= 0;
+				end else if (ie && irq)
 					opcode <= `INSN_VOP_INTR;
 				else
-					opcode <= busdata;
+					opcode <= {0,busdata};
 				rdata <= busdata;
 				newcycle <= 0;
 				cycle <= 0;