X-Git-Url: http://git.joshuawise.com/firearm.git/blobdiff_plain/dfe0713aebc58dd093c309011ac0596597ab2cb5..a4c270c74d821e221d30d405bca8676963f29340:/Execute.v diff --git a/Execute.v b/Execute.v index 38a192f..6582581 100644 --- a/Execute.v +++ b/Execute.v @@ -57,7 +57,7 @@ module Execute( .in0(alu_in0), .in1(alu_in1), .cpsr(cpsr), .op(alu_op), .setflags(alu_setflags), .shifter_carry(carry), .result(alu_result), .cpsr_out(alu_outcpsr), .setres(alu_setres)); - + always @(posedge clk) begin if (!stall) @@ -75,6 +75,13 @@ module Execute( outop2 <= op2; end end + + reg delayedflush = 0; + always @(posedge clk) + if (flush && outstall /* halp! I can't do it now, maybe later? */) + delayedflush <= 1; + else if (!outstall /* anything has been handled this time around */) + delayedflush <= 0; reg prevstall = 0; always @(posedge clk) @@ -83,7 +90,7 @@ module Execute( always @(*) begin outstall = stall; - next_outbubble = inbubble | flush; + next_outbubble = inbubble | flush | delayedflush; next_outcpsr = cpsr; next_outspsr = spsr; next_write_reg = 0; @@ -114,8 +121,8 @@ module Execute( mult_in1 = op2 /* Rs */; $display("New MUL instruction"); end - outstall = stall | ((!prevstall | !mult_done) && !inbubble); - next_outbubble = inbubble | !mult_done | !prevstall; + outstall = outstall | ((!prevstall | !mult_done) && !inbubble); + next_outbubble = next_outbubble | !mult_done | !prevstall; next_outcpsr = insn[20] /* S */ ? {mult_result[31] /* N */, mult_result == 0 /* Z */, 1'b0 /* C */, cpsr[28] /* V */, cpsr[27:0]} : cpsr; next_write_reg = 1; next_write_num = insn[19:16] /* Rd -- why the fuck isn't this the same place as ALU */; @@ -171,12 +178,12 @@ module Execute( begin end `DECODE_BRANCH: begin - if(!inbubble) begin + if(!inbubble && !flush && !delayedflush) begin jmppc = pc + op0 + 32'h8; if(insn[24]) begin next_write_reg = 1; next_write_num = 4'hE; /* link register */ - next_write_data = pc - 32'h4; + next_write_data = pc + 32'h4; end jmp = 1'b1; end @@ -251,7 +258,7 @@ module ALU( 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 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]);