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more work on ALU

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This commit is contained in:
Raphael Jacquot 2019-02-10 23:00:06 +01:00
parent 799fc3c327
commit 43dd894888
2 changed files with 21 additions and 4 deletions
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4
opcodes/B[ab]x.v
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@ -30,4 +30,8 @@
next_cycle <= `BUSCMD_NOP;
decstate <= `DEC_ALU_INIT;
alu_return <= `DEC_START;
`ifdef SIM
`endif
end

21
opcodes/z_alu_phase_3.v
View file

@ -22,28 +22,41 @@
`ALU_REG_B: B[alu_first*4+:4] <= 0;
`ALU_REG_C: C[alu_first*4+:4] <= 0;
`ALU_REG_D: D[alu_first*4+:4] <= 0;
default: $display("ALU_OP_ZERO register not handled");
default: begin
$display("ALU_OP_ZERO register not handled");
alu_requested_halt <= 1;
end
endcase
alu_first <= (alu_first + 1) & 4'hF;
end
`ALU_OP_2CMPL: begin
case (alu_reg_dest)
`ALU_REG_A: {Carry, A[alu_first*4+:4]} <= !alu_src1 + alu_carry;
default: $display("ALU_OP_2CMPL register not handled");
default: begin
$display("ALU_OP_2CMPL register not handled");
alu_requested_halt <= 1;
end
endcase
alu_first <= (alu_first + 1) & 4'hF;
end
`ALU_OP_1CMPL: begin
case (alu_reg_dest)
`ALU_REG_A: A[alu_first*4+:4] <= ~alu_src1;
default: $display("ALU_OP_1CMPL register not handled");
`ALU_REG_C: C[alu_first*4+:4] <= ~alu_src1;
default: begin
$display("ALU_OP_1CMPL register not handled");
alu_requested_halt <= 1;
end
endcase
alu_first <= (alu_first + 1) & 4'hF;
end
`ALU_OP_INC: begin
case (alu_reg_dest)
`ALU_REG_D: {Carry, D[alu_first*4+:4]} <= alu_src1 + alu_carry;
default: $display("ALU_OP_INC register not handled");
default: begin
$display("ALU_OP_INC register not handled");
alu_requested_halt <= 1;
end
endcase
alu_first <= (alu_first + 1) & 4'hF;
end