X-Git-Url: http://git.joshuawise.com/firearm.git/blobdiff_plain/af096d96b3a5de1f24fc3520b209d9b6a8b946f2..314dac2128239e7e115f42540d86e8d2642eb0fa:/Execute.v

diff --git a/Execute.v b/Execute.v
index ea6cd60..34c62af 100644
--- a/Execute.v
+++ b/Execute.v
@@ -19,7 +19,9 @@ module Execute(
 	output reg [31:0] outcpsr = 0,
 	output reg write_reg = 1'bx,
 	output reg [3:0] write_num = 4'bxxxx,
-	output reg [31:0] write_data = 32'hxxxxxxxx
+	output reg [31:0] write_data = 32'hxxxxxxxx,
+	output reg [31:0] outpc
+	output reg outflush
 	);
 	
 	reg mult_start;
@@ -129,8 +131,17 @@ module Execute(
 		end
 		`DECODE_LDRSTR_UNDEFINED,	/* Undefined. I hate ARM */
 		`DECODE_LDRSTR,		/* Single data transfer */
-		`DECODE_LDMSTM,		/* Block data transfer */
-		`DECODE_BRANCH,		/* Branch */
+		`DECODE_LDMSTM:		/* Block data transfer */
+		begin end
+		`DECODE_BRANCH:
+		begin
+			outpc = pc + op0;
+			if(insn[24]) begin
+				next_write_reg = 1;
+				next_write_num = 4'hE; /* link register */
+				next_write_data = pc + 32'h4;
+			end
+		end                     /* Branch */
 		`DECODE_LDCSTC,		/* Coprocessor data transfer */
 		`DECODE_CDP,		/* Coprocessor data op */
 		`DECODE_MRCMCR,		/* Coprocessor register transfer */
@@ -179,7 +190,6 @@ module Multiplier(
 	end
 endmodule
 
-/* XXX is the interface correct? */
 module ALU(
 	input clk,
 	input Nrst,	/* XXX not used yet */
@@ -198,12 +208,15 @@ module ALU(
 	wire [31:0] res;
 	wire flag_n, flag_z, flag_c, flag_v, setres;
 	wire [32:0] sum, diff, rdiff;
+	wire sum_v, diff_v, rdiff_v;
 
 	assign sum = {1'b0, in0} + {1'b0, in1};
 	assign diff = {1'b0, in0} - {1'b0, in1};
 	assign rdiff = {1'b0, in1} + {1'b0, in0};
+	assign sum_v = (in0[31] ^~ in1[31]) & (sum[31] ^ in0[31]);
+	assign diff_v = (in0[31] ^ in1[31]) & (diff[31] ^ in0[31]);
+	assign rdiff_v = (in0[31] ^ in1[31]) & (rdiff[31] ^ in1[31]);
 
-	/* TODO XXX flag_v not set correctly */
 	always @(*) begin
 		res = 32'hxxxxxxxx;
 		setres = 1'bx;
@@ -222,26 +235,32 @@ module ALU(
 		end
 		`ALU_SUB: begin
 			{flag_c, result} = diff;
+			flag_v = diff_v;
 			setres = 1'b1;
 		end
 		`ALU_RSB: begin
 			{flag_c, result} = rdiff;
+			flag_v = rdiff_v;
 			setres = 1'b1;
 		end
 		`ALU_ADD: begin
 			{flag_c, result} = sum;
+			flag_v = sum_v;
 			setres = 1'b1;
 		end
 		`ALU_ADC: begin
 			{flag_c, result} = sum + {32'b0, cpsr[`CPSR_C]};
+			flag_v = sum_v | (~sum[31] & result[31]);
 			setres = 1'b1;
 		end
 		`ALU_SBC: begin
 			{flag_c, result} = diff - {32'b0, (~cpsr[`CPSR_C])};
+			flag_v = diff_v | (diff[31] & ~result[31]);
 			setres = 1'b1;
 		end
 		`ALU_RSC: begin
 			{flag_c, result} = rdiff - {32'b0, (~cpsr[`CPSR_C])};
+			flag_v = rdiff_v | (rdiff[31] & ~result[31]);
 			setres = 1'b1;
 		end
 		`ALU_TST: begin
@@ -256,10 +275,12 @@ module ALU(
 		end
 		`ALU_CMP: begin
 			{flag_c, result} = diff;
+			flag_v = diff_v;
 			setres = 1'b0;
 		end
 		`ALU_CMN: begin
 			{flag_c, result} = sum;
+			flag_v = sum_v;
 			setres = 1'b0;
 		end
 		`ALU_ORR: begin