Memory: Change offset latch in LDM so that there is no flutter if DCache cannot get...

[firearm.git] / Execute.v

diff --git a/Execute.v b/Execute.v
index 06912a2f2a625bdf7d9039004cd77a3645cc0c06..65825810a42b8b468504f9af2b072d9bbc635aae 100644 (file)
--- a/Execute.v
+++ b/Execute.v
@@ -22,8 +22,11 @@ module Execute(
        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] jmppc,
+       output reg jmp,
        output reg [31:0] outpc,
-       output reg outflush
+       output reg [31:0] outinsn,
+       output reg [31:0] outop0, outop1, outop2
        );
        
        reg mult_start;
@@ -41,8 +44,9 @@ module Execute(
        reg [31:0] next_outcpsr, next_outspsr;
        reg next_write_reg;
        reg [3:0] next_write_num;
+
        reg [31:0] next_write_data;
-       
+
        Multiplier multiplier(
                .clk(clk), .Nrst(Nrst),
                .start(mult_start), .acc0(mult_acc0), .in0(mult_in0),
@@ -53,7 +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)
@@ -64,8 +68,20 @@ module Execute(
                        write_reg <= next_write_reg;
                        write_num <= next_write_num;
                        write_data <= next_write_data;
+                       outpc <= pc;
+                       outinsn <= insn;
+                       outop0 <= op0;
+                       outop1 <= op1;
+                       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)
@@ -74,23 +90,26 @@ module Execute(
        always @(*)
        begin
                outstall = stall;
-               next_outbubble = inbubble;
+               next_outbubble = inbubble | flush | delayedflush;
                next_outcpsr = cpsr;
                next_outspsr = spsr;
                next_write_reg = 0;
                next_write_num = 4'hx;
                next_write_data = 32'hxxxxxxxx;
-       
+
                mult_start = 0;
                mult_acc0 = 32'hxxxxxxxx;
                mult_in0 = 32'hxxxxxxxx;
                mult_in1 = 32'hxxxxxxxx;
-       
+
                alu_in0 = 32'hxxxxxxxx;
                alu_in1 = 32'hxxxxxxxx;
                alu_op = 4'hx;  /* hax! */
                alu_setflags = 1'bx;
-               
+
+               jmp = 1'b0;
+               jmppc = 32'h00000000;
+
                casez (insn)
                `DECODE_ALU_MULT:       /* Multiply -- must come before ALU, because it pattern matches a specific case of ALU */
                begin
@@ -102,8 +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 */;
@@ -159,11 +178,14 @@ module Execute(
                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;
+                       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;
+                               end
+                               jmp = 1'b1;
                        end
                end                     /* Branch */
                `DECODE_LDCSTC,         /* Coprocessor data transfer */
@@ -229,14 +251,14 @@ module ALU(
        output reg [31:0] cpsr_out,
        output reg setres
 );
-       wire [31:0] res;
-       wire flag_n, flag_z, flag_c, flag_v, setres;
+       reg [31:0] res;
+       reg flag_n, flag_z, flag_c, flag_v;
        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 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]);