X-Git-Url: http://git.joshuawise.com/firearm.git/blobdiff_plain/732b7730ab749590dcf0e05b3c9a0669bfd24418..af096d96b3a5de1f24fc3520b209d9b6a8b946f2:/Execute.v diff --git a/Execute.v b/Execute.v index ac759bb..ea6cd60 100644 --- a/Execute.v +++ b/Execute.v @@ -62,6 +62,10 @@ module Execute( end end + reg prevstall = 0; + always @(posedge clk) + prevstall <= outstall; + always @(*) begin outstall = stall; @@ -71,13 +75,34 @@ module Execute( 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; casez (insn) - `DECODE_ALU_MULT, /* Multiply -- must come before ALU, because it pattern matches a specific case of ALU */ + `DECODE_ALU_MULT: /* Multiply -- must come before ALU, because it pattern matches a specific case of ALU */ + begin + if (!prevstall && !inbubble) + begin + mult_start = 1; + mult_acc0 = insn[21] /* A */ ? op0 /* Rn */ : 32'h0; + mult_in0 = op1 /* Rm */; + mult_in1 = op2 /* Rs */; + $display("New MUL instruction"); + end + outstall = stall | ((!prevstall | !mult_done) && !inbubble); + next_outbubble = inbubble | !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 */; + next_write_data = mult_result; + end // `DECODE_ALU_MUL_LONG, /* Multiply long */ `DECODE_ALU_MRS, /* MRS (Transfer PSR to register) */ `DECODE_ALU_MSR, /* MSR (Transfer register to PSR) */