diff --git a/alu.v b/alu.v index d813cc6..1389477 100644 --- a/alu.v +++ b/alu.v @@ -36,76 +36,83 @@ assign JC8 = (Rs1 < 0); always @(*) begin - case (opcode) - 6'b000000: alusum = {1'b1, Rd}; // JMP Unconditional Jump, first bit high to indicate jump and passes through Rd - - 6'b000100: alusum = {JC1, Rd}; // JC1 Conditional Jump A < B - 6'b000101: alusum = {JC2, Rd}; // JC2 Conditional Jump A > B - 6'b000110: alusum = {JC3, Rd}; // JC3 Conditional Jump A = B - 6'b000111: alusum = {JC4, Rd}; // JC4 Conditional Jump A = 0 - - 6'b001000: alusum = {JC5, Rd}; // JC5 Conditional Jump A >= B / A !< B - 6'b001001: alusum = {JC6, Rd}; // JC6 Conditional Jump A <= B / A !> B - 6'b001010: alusum = {JC7, Rd}; // JC7 Conditional Jump A != B - 6'b001011: alusum = {JC8, Rd}; // JC8 Conditional Jump A < 0 - - 6'b001100: alusum = {1'b0, Rs1 & Rs2}; // AND Bitwise AND - 6'b001101: alusum = {1'b0, Rs1 | Rs2}; // OR Bitwise OR - 6'b001110: alusum = {1'b0, Rs1 ^ Rs2}; // XOR Bitwise XOR - 6'b001111: alusum = {1'b0, ~Rs1}; // NOT Bitwise NOT - - 6'b010000: alusum = {1'b0, ~Rs1 | ~Rs2}; // NND Bitwise NAND - 6'b010001: alusum = {1'b0, ~Rs1 & ~Rs2}; // NOR Bitwise NOR - 6'b010010: alusum = {1'b0, Rs1 ~^ Rs2}; // XNR Bitwise XNOR - 6'b010011: alusum = {1'b0, Rs1}; // MOV Move (Rd = Rs1) - - 6'b010100: alusum = {1'b0, Rs1} + {1'b0, Rs2}; // ADD Add (Rd = Rs1 + Rs2) - 6'b010101: alusum = {1'b0, Rs1} + {1'b0, Rs2} + carryin; // ADC Add w/ Carry (Rd = Rs1 + Rs2 + C) - 6'b010110: alusum = {1'b0, Rs1} + {17'b00000000000000001}; // ADO Add 1 (Rd = Rd + 1) - 6'b010111: ; - - 6'b011000: alusum = {1'b0, Rs1} - {1'b0, Rs2}; // SUB Subtract (Rd = Rs1 - Rs2) - 6'b011001: alusum = {1'b0, Rs1} - {1'b0, Rs2} + carryin - {17'b00000000000000001}; // SBC Subtract w/ Carry (Rd = Rs1 - Rs2 + C - 1) - 6'b011010: alusum = {1'b0, Rs1} - {17'b00000000000000001}; // SBO Subtract 1 (Rd = Rd - 1) - 6'b011011: ; - - 6'b011100: // MUL Multiply (Rd = Rs1 * Rs2) - begin -// mul1 = Rs1; -// mul2 = Rs2; - alusum[16] = 1'b0; - {mulextra, alusum[15:0]} = Rs1 * Rs2; - end - 6'b011101: // MLA Multiply and Add (Rd = Rs2 + (Rd * Rs1)) - begin -// mul1 = Rs1; -// mul2 = Rs2; - alusum[16] = 1'b0; - {mulextra, alusum[15:0]} = (Rd * Rs1) + Rs2; - end - 6'b011110: // MLS Multiply and Subtract (Rd = Rs2 - (Rd * Rs1)[15:0]) - begin -// mul1 = Rs1; -// mul2 = Rs2; - alusum = {1'b0, Rs2 - (Rd * Rs1)}; - end - 6'b011111: alusum = mulextra; // MRT Retrieve Multiply MSBs (Rd = MSBs) - - 6'b100000: alusum = {1'b0, Rs1 << Rs2}; // LSL Logical Shift Left (Rd = Rs1 shifted left by value of Rs2) - 6'b100001: alusum = {1'b0, Rs1 >> Rs2}; // LSR Logical Shift Right (Rd = Rs1 shifted right by value of Rs2) - 6'b100010: alusum = {Rs1[15], Rs1 >>> Rs2}; // ASR Arithmetic Shift Right (Rd = Rs1 shifted right by value of Rs2, maintaining sign bit) - 6'b100011: ; - - 6'b100100: alusum = {1'b0, (Rs1 >> Rs2[3:0]) | (Rs1 << (16 - Rs2[3:0]))}; // ROR Shift Right Loop (Rd = Rs1 shifted right by Rs2, but Rs1[0] -> Rs1[15]) - 6'b100101: alusum = ({Rs1, carryin} >> Rs2[3:0]) | ({Rs1, carryin} << (17 - (Rs2 % 17)));// RRC Shift Right Loop w/ Carry (Rd = Rs1 shifted right by Rs2, but Rs1[0] -> Carry & Carry -> Rs1[15]) - 6'b100110: ; - 6'b100111: ; - - 6'b111110: ; // NOP No Operation (Do Nothing for a cycle) - 6'b111111: ; // STP Stop (Program Ends) - - default: ; // During Load & Store as well as undefined opcodes - endcase; + if(!enable) + begin + case (opcode) + 6'b000000: alusum = {1'b1, Rd}; // JMP Unconditional Jump, first bit high to indicate jump and passes through Rd + + 6'b000100: alusum = {JC1, Rd}; // JC1 Conditional Jump A < B + 6'b000101: alusum = {JC2, Rd}; // JC2 Conditional Jump A > B + 6'b000110: alusum = {JC3, Rd}; // JC3 Conditional Jump A = B + 6'b000111: alusum = {JC4, Rd}; // JC4 Conditional Jump A = 0 + + 6'b001000: alusum = {JC5, Rd}; // JC5 Conditional Jump A >= B / A !< B + 6'b001001: alusum = {JC6, Rd}; // JC6 Conditional Jump A <= B / A !> B + 6'b001010: alusum = {JC7, Rd}; // JC7 Conditional Jump A != B + 6'b001011: alusum = {JC8, Rd}; // JC8 Conditional Jump A < 0 + + 6'b001100: alusum = {1'b0, Rs1 & Rs2}; // AND Bitwise AND + 6'b001101: alusum = {1'b0, Rs1 | Rs2}; // OR Bitwise OR + 6'b001110: alusum = {1'b0, Rs1 ^ Rs2}; // XOR Bitwise XOR + 6'b001111: alusum = {1'b0, ~Rs1}; // NOT Bitwise NOT + + 6'b010000: alusum = {1'b0, ~Rs1 | ~Rs2}; // NND Bitwise NAND + 6'b010001: alusum = {1'b0, ~Rs1 & ~Rs2}; // NOR Bitwise NOR + 6'b010010: alusum = {1'b0, Rs1 ~^ Rs2}; // XNR Bitwise XNOR + 6'b010011: alusum = {1'b0, Rs1}; // MOV Move (Rd = Rs1) + + 6'b010100: alusum = {1'b0, Rs1} + {1'b0, Rs2}; // ADD Add (Rd = Rs1 + Rs2) + 6'b010101: alusum = {1'b0, Rs1} + {1'b0, Rs2} + carryin; // ADC Add w/ Carry (Rd = Rs1 + Rs2 + C) + 6'b010110: alusum = {1'b0, Rs1} + {17'b00000000000000001}; // ADO Add 1 (Rd = Rd + 1) + 6'b010111: ; + + 6'b011000: alusum = {1'b0, Rs1} - {1'b0, Rs2}; // SUB Subtract (Rd = Rs1 - Rs2) + 6'b011001: alusum = {1'b0, Rs1} - {1'b0, Rs2} + carryin - {17'b00000000000000001}; // SBC Subtract w/ Carry (Rd = Rs1 - Rs2 + C - 1) + 6'b011010: alusum = {1'b0, Rs1} - {17'b00000000000000001}; // SBO Subtract 1 (Rd = Rd - 1) + 6'b011011: ; + + 6'b011100: // MUL Multiply (Rd = Rs1 * Rs2) + begin +// mul1 = Rs1; +// mul2 = Rs2; + alusum[16] = 1'b0; + {mulextra, alusum[15:0]} = Rs1 * Rs2; + end + 6'b011101: // MLA Multiply and Add (Rd = Rs2 + (Rd * Rs1)) + begin +// mul1 = Rs1; +// mul2 = Rs2; + alusum[16] = 1'b0; + {mulextra, alusum[15:0]} = (Rd * Rs1) + Rs2; + end + 6'b011110: // MLS Multiply and Subtract (Rd = Rs2 - (Rd * Rs1)[15:0]) + begin +// mul1 = Rs1; +// mul2 = Rs2; + alusum = {1'b0, Rs2 - (Rd * Rs1)}; + end + 6'b011111: alusum = mulextra; // MRT Retrieve Multiply MSBs (Rd = MSBs) + + 6'b100000: alusum = {1'b0, Rs1 << Rs2}; // LSL Logical Shift Left (Rd = Rs1 shifted left by value of Rs2) + 6'b100001: alusum = {1'b0, Rs1 >> Rs2}; // LSR Logical Shift Right (Rd = Rs1 shifted right by value of Rs2) + 6'b100010: alusum = {Rs1[15], Rs1 >>> Rs2}; // ASR Arithmetic Shift Right (Rd = Rs1 shifted right by value of Rs2, maintaining sign bit) + 6'b100011: ; + + 6'b100100: alusum = {1'b0, (Rs1 >> Rs2[3:0]) | (Rs1 << (16 - Rs2[3:0]))}; // ROR Shift Right Loop (Rd = Rs1 shifted right by Rs2, but Rs1[0] -> Rs1[15]) + 6'b100101: alusum = ({Rs1, carryin} >> (Rs2 % 17)) | ({Rs1, carryin} << (17 - (Rs2 % 17)));// RRC Shift Right Loop w/ Carry (Rd = Rs1 shifted right by Rs2, but Rs1[0] -> Carry & Carry -> Rs1[15]) + 6'b100110: ; + 6'b100111: ; + + 6'b111110: ; // NOP No Operation (Do Nothing for a cycle) + 6'b111111: ; // STP Stop (Program Ends) + + default: ; // During Load & Store as well as undefined opcodes + endcase; + end + else + begin + alusum = {1'b0, 16'h0000}; // Bring output low during Load/Store so it does not interfere + end end /*