From: Joshua Wise <joshua@rebirth.joshuawise.com>
Date: Mon, 31 Mar 2008 06:58:27 +0000 (-0400)
Subject: Fix RAM bugs with kludge. Fix CALL bug. CALL test case.
X-Git-Url: http://git.joshuawise.com/fpgaboy.git/commitdiff_plain/4f9c2edfd1242be9e98667d39393c829fcd826c8?hp=ef6fbe3130c958177759bd99cf24a6c3edc4693c

Fix RAM bugs with kludge. Fix CALL bug. CALL test case.
---

diff --git a/FPGABoy.ise b/FPGABoy.ise
index 5ae1765..8ee44c4 100644
Binary files a/FPGABoy.ise and b/FPGABoy.ise differ
diff --git a/GBZ80Core.v b/GBZ80Core.v
index cb231c2..ec1756e 100644
--- a/GBZ80Core.v
+++ b/GBZ80Core.v
@@ -395,16 +395,18 @@ module GBZ80Core(
 						rd <= 1;
 					end
 				2:	begin
+						`EXEC_INC_PC;
+					end
+				3:	begin
 						address <= {registers[`REG_SPH],registers[`REG_SPL]} - 1;
 						wdata <= registers[`REG_PCH];
 						wr <= 1;
 					end
-				3:	begin
+				4:	begin
 						address <= {registers[`REG_SPH],registers[`REG_SPL]} - 2;
 						wdata <= registers[`REG_PCL];
 						wr <= 1;
 					end
-				4:	begin /* nothing happens on the bus next cycle! */ end
 				5:	begin
 						`EXEC_NEWCYCLE;	/* do NOT increment the PC */
 					end
@@ -680,15 +682,15 @@ module GBZ80Core(
 					end
 				3: begin
 						cycle <= 4;
-						registers[`REG_PCH] <= tmp2;
 					end
 				4: begin
 						cycle <= 5;
-						registers[`REG_PCL] <= tmp;
+						registers[`REG_PCH] <= tmp2;
 					end
 				5: begin
 						{registers[`REG_SPH],registers[`REG_SPL]} <=
 							{registers[`REG_SPH],registers[`REG_SPL]} - 2;
+						registers[`REG_PCL] <= tmp;
 						cycle <= 0;
 					end
 				endcase
@@ -715,16 +717,15 @@ module ROM(
 	wire idata = data;
 	assign data = (rd && decode) ? odata : 8'bzzzzzzzz;
 	
-	always @(wr or rd)
-	begin
-		if (decode && rd)
+	always @(posedge rd)
+		if (decode)
 			odata <= rom[address];
-	end
 endmodule
 
 module InternalRAM(
 	input [15:0] address,
 	inout [7:0] data,
+	input clk,
 	input wr, rd);
 	
 	reg [7:0] ram [8191:0];
@@ -734,12 +735,17 @@ module InternalRAM(
 	wire idata = data;
 	assign data = (rd && decode) ? odata : 8'bzzzzzzzz;
 	
-	always @(rd or wr)
+	reg [13:0] diq;
+	initial
+		for (diq = 0; diq < 8191; diq = diq + 1)
+			ram[diq] = 8'h43;
+	
+	always @(negedge clk)
 	begin
 		if (decode && rd)
-			odata <= ram[address];
-		else if (decode && wr)
-			ram[address] <= idata;
+			odata <= ram[address[12:0]];
+		if (decode && wr)
+			ram[address[12:0]] <= data;
 	end
 endmodule
 
@@ -766,6 +772,7 @@ module TestBench();
 	InternalRAM ram(
 		.address(addr),
 		.data(data),
+		.clk(clk),
 		.wr(wr),
 		.rd(rd));
 endmodule
diff --git a/rom.hex b/rom.hex
index 0cef4b0..5ff2d7a 100644
--- a/rom.hex
+++ b/rom.hex
@@ -1,16 +1,18 @@
-// LD HL, 0100
-21
-00
+// LD SP, DFFFh
+31
+FF
+DF
+// CALL 0080h
+CD
+80
+01
+// CALL 0080h
+CD
+80
 01
-// LD SP, HL
-F9
-// RET
-C9
-
-@80
 // RST 00h
 C7
 
-@100
-80
-00
\ No newline at end of file
+@180
+// RET
+C9