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-rw-r--r--alu_stage.v21
-rw-r--r--nqcpu.v17
2 files changed, 34 insertions, 4 deletions
diff --git a/alu_stage.v b/alu_stage.v
index 3761f25..7bdbfe8 100644
--- a/alu_stage.v
+++ b/alu_stage.v
@@ -20,6 +20,10 @@ module alu_stage (
input [15:0] memData_in, // read in from memory
output reg [15:0] memData_out, // to write out to memory
+ // setting PC
+ output setPC,
+ output [15:0] setPCValue,
+
output reg [32:0] control_signals_out,
output reg [15:0] imm_out,
output reg [15:0] pc_out,
@@ -90,14 +94,29 @@ module alu_stage (
.carry(aluCarry)
);
+ wire setRegZCond, setRegCCond, setSomeReg;
+ assign setRegZCond = setRegCond_in[4] | (setRegCond_in[3] == statusReg[1]);
+ assign setRegCCond = setRegCond_in[1] | (setRegCond_in[0] == statusReg[0]);
+ assign setSomeReg =
+ en &
+ setRegCond_in[5] &
+ (
+ setRegCond_in[2] ?
+ (setRegZCond & setRegCCond) :
+ (setRegZCond | setRegCCond)
+ );
+
assign rf_regA = aluReg1_in;
assign rf_regB = aluReg2_in;
- assign rf_we = en & (regSetH_in | regSetL_in);
+ assign rf_we = setSomeReg & !aluDest_in;
assign rf_hb = regSetH_in;
assign rf_lb = regSetL_in;
assign rf_dataIn = aluResult;
assign rf_regDest = regDest_in;
+ assign setPC = setSomeReg & aluDest_in;
+ assign setPCValue = aluResult;
+
always @(posedge clk) begin
if(en) begin
control_signals_out <= control_signals_in;
diff --git a/nqcpu.v b/nqcpu.v
index 34935c6..c27c742 100644
--- a/nqcpu.v
+++ b/nqcpu.v
@@ -31,6 +31,9 @@ module nqcpu (
output [15:0] dbg_r7,
output [9:0] dbg_state,
+ output dbg_setPC,
+ output [15:0] dbg_setPCValue,
+
output [1:0] dbg_statusreg
);
@@ -40,7 +43,8 @@ module nqcpu (
pc = 16'h0;
end
- wire fetch_en, decode_en, alu_en, incr_pc;
+ wire fetch_en, decode_en, alu_en, incr_pc, setPC;
+ wire [15:0] setPCValue;
wire fetch_ready;
wire [15:0] fetched_instr;
@@ -58,6 +62,9 @@ module nqcpu (
if(incr_pc) begin
pc <= pc + 16'h2;
end
+ else if (setPC & alu_en) begin
+ pc <= setPCValue;
+ end
end
wire [32:0] ctrl_from_decoder;
@@ -130,6 +137,9 @@ module nqcpu (
.memData_in(16'hDEAD), // read in from memory
//.memData_out(??), // to write out to memory
+ .setPC(setPC),
+ .setPCValue(setPCValue),
+
.control_signals_out(ctrl_from_alu),
.imm_out(imm_from_alu),
.pc_out(pc_from_alu),
@@ -174,6 +184,7 @@ module nqcpu (
.setRegCond(debugSetRegCond)
);
- assign debugPC = pc_from_alu;
-
+ assign debugPC = pc;
+ assign dbg_setPC = setPC;
+ assign dbg_setPCValue = setPCValue;
endmodule