X-Git-Url: http://git.joshuawise.com/firearm.git/blobdiff_plain/a4c270c74d821e221d30d405bca8676963f29340..1bc060d94b6e0978c8bdf85795506ab4ed921225:/Execute.v diff --git a/Execute.v b/Execute.v index 6582581..ac446aa 100644 --- a/Execute.v +++ b/Execute.v @@ -19,6 +19,7 @@ module Execute( output reg outbubble = 1, output reg [31:0] outcpsr = 0, output reg [31:0] outspsr = 0, + output reg outcpsrup = 0, output reg write_reg = 1'bx, output reg [3:0] write_num = 4'bxxxx, output reg [31:0] write_data = 32'hxxxxxxxx, @@ -42,6 +43,7 @@ module Execute( reg next_outbubble; reg [31:0] next_outcpsr, next_outspsr; + reg next_outcpsrup; reg next_write_reg; reg [3:0] next_write_num; @@ -65,6 +67,7 @@ module Execute( outbubble <= next_outbubble; outcpsr <= next_outcpsr; outspsr <= next_outspsr; + outcpsrup <= next_outcpsrup; write_reg <= next_write_reg; write_num <= next_write_num; write_data <= next_write_data; @@ -93,6 +96,7 @@ module Execute( next_outbubble = inbubble | flush | delayedflush; next_outcpsr = cpsr; next_outspsr = spsr; + next_outcpsrup = 0; next_write_reg = 0; next_write_num = 4'hx; next_write_data = 32'hxxxxxxxx; @@ -124,6 +128,7 @@ module Execute( 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_outcpsrup = insn[20] /* S */; 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; @@ -137,9 +142,11 @@ module Execute( next_write_data = spsr; else next_write_data = cpsr; + next_outcpsrup = 1; end `DECODE_ALU_MSR, /* MSR (Transfer register to PSR) */ `DECODE_ALU_MSR_FLAGS: /* MSR (Transfer register or immediate to PSR, flag bits only) */ + begin if ((cpsr[4:0] == `MODE_USR) || (insn[16] /* that random bit */ == 1'b0)) /* flags only */ begin if (insn[22] /* Ps */) @@ -152,6 +159,8 @@ module Execute( else next_outcpsr = op0; end + next_outcpsrup = 1; + end `DECODE_ALU_SWP, /* Atomic swap */ `DECODE_ALU_BX, /* Branch */ `DECODE_ALU_HDATA_REG, /* Halfword transfer - register offset */ @@ -171,6 +180,7 @@ module Execute( end next_outcpsr = ((insn[15:12] == 4'b1111) && insn[20]) ? spsr : alu_outcpsr; + next_outcpsrup = insn[20] /* S */; end `DECODE_LDRSTR_UNDEFINED, /* Undefined. I hate ARM */ `DECODE_LDRSTR, /* Single data transfer */ @@ -178,7 +188,7 @@ module Execute( begin end `DECODE_BRANCH: begin - if(!inbubble && !flush && !delayedflush) begin + if(!inbubble && !flush && !delayedflush && !outstall /* Let someone else take precedence. */) begin jmppc = pc + op0 + 32'h8; if(insn[24]) begin next_write_reg = 1; @@ -281,11 +291,13 @@ module ALU( end `ALU_SUB: begin {flag_c, result} = diff; + flag_c = !flag_c; flag_v = diff_v; setres = 1'b1; end `ALU_RSB: begin {flag_c, result} = rdiff; + flag_c = !flag_c; flag_v = rdiff_v; setres = 1'b1; end @@ -301,11 +313,13 @@ module ALU( end `ALU_SBC: begin {flag_c, result} = diff - {32'b0, (~cpsr[`CPSR_C])}; + flag_c = !flag_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_c = !flag_c; flag_v = rdiff_v | (rdiff[31] & ~result[31]); setres = 1'b1; end @@ -321,6 +335,7 @@ module ALU( end `ALU_CMP: begin {flag_c, result} = diff; + flag_c = !flag_c; flag_v = diff_v; setres = 1'b0; end