`timescale 1ns / 1 ps
module RISC5(   // translated from Lola
input clk, rst, stallX,
input [31:0] inbus, codebus,
output [23:0] adr,
output rd, wr, ben,
output [31:0] outbus);
reg [21:0] PC;
reg [31:0] IR;
reg N, Z, C, OV, stall1, PMsel;
reg [31:0] R[15:0];
reg [31:0] H;
wire [21:0] pcmux, nxpc;
wire cond, S, sa, sb, sc;
wire [31:0] ins, pmout;
wire p, q, u, v, w;
wire [3:0] op, ira, ira0, irb, irc;
wire [2:0] cc;
wire [15:0] imm;
wire [19:0] off;
wire [23:0] offL;
wire regwr, stall, stallL, stallM, stallD, stallFA, stallFM, stallFD;
wire [1:0] sc1, sc0;
wire a0, a1, a2, a3;
wire [7:0] inbusL, outbusB0, outbusB1, outbusB2, outbusB3;
wire [23:0] inbusH;
wire [31:0] A, B, C0, C1, aluRes, regmux, s1, s2, s3, t1, t2, t3, quotient, remainder;
wire [63:0] product;
wire [31:0] fsum, fprod, fquot;
wire Add, Sub, Mul, Div, Fadd, Fsub, Fmul, Fdiv, Ldr, Str, Br;
assign adr = stallL ? (B[23:0] + {4'h0, off}) : {pcmux, 2'h0};
assign rd = ((Ldr & ~stallX) & ~stall1);
assign wr = ((Str & ~stallX) & ~stall1);
assign ben = ((((p & ~q) & v) & ~stallX) & ~stall1);
assign outbus = {outbusB3, outbusB2, outbusB1, outbusB0};
PROM PM(.clk(clk), .adr(pcmux[8:0]), .data(pmout));
Multiplier mulUnit(.clk(clk), .run(Mul), .u(~u), .stall(stallM), .x(B), .y(C1), .z(product));
Divider divUnit(.clk(clk), .run(Div), .u(~u), .stall(stallD), .x(B), .y(C1), .quot(quotient), .rem(remainder));
FPAdder faddUnit(.clk(clk), .run((Fadd | Fsub)), .u(u), .v(v), .stall(stallFA), .x(B), .y({(Fsub ^ C0[31]), C0[30:0]}), .z(fsum));
FPMultiplier fmulUnit(.clk(clk), .run(Fmul), .stall(stallFM), .x(B), .y(C0), .z(fprod));
FPDivider fdivUnit(.clk(clk), .run(Fdiv), .stall(stallFD), .x(B), .y(C0), .z(fquot));
assign pcmux = ~rst ? 22'h3FF800 : stall ? PC : ((Br & cond) & u) ? (offL[21:0] + nxpc) : ((Br & cond) & ~u) ? C0[23:2] : nxpc;
assign nxpc = (PC + 1);
assign cond = (ins[27] ^ (((((((((cc == 0) & N) | ((cc == 1) & Z)) | ((cc == 2) & C)) | ((cc == 3) & OV)) | ((cc == 4) & (C | Z))) | ((cc == 5) & S)) | ((cc == 6) & (S | Z))) | (cc == 7)));
assign S = (N ^ OV);
assign sa = aluRes[31];
assign sb = B[31];
assign sc = C1[31];
assign ins = PMsel ? pmout : IR;
assign p = ins[31];
assign q = ins[30];
assign u = ins[29];
assign v = ins[28];
assign w = ins[16];
assign op = ins[19:16];
assign ira = ins[27:24];
assign ira0 = Br ? 4'hF : ira;
assign irb = ins[23:20];
assign irc = ins[3:0];
assign cc = ins[26:24];
assign imm = ins[15:0];
assign off = ins[19:0];
assign offL = ins[23:0];
assign regwr = (((~p & ~stall) | ((Ldr & ~stallX) & ~stall1)) | (((Br & cond) & v) & ~stallX));
assign stall = ((((((stallL | stallM) | stallD) | stallFA) | stallFM) | stallFD) | stallX);
assign stallL = ((Ldr | Str) & ~stall1);
assign sc1 = C1[3:2];
assign sc0 = C1[1:0];
assign a0 = (~adr[1] & ~adr[0]);
assign a1 = (~adr[1] & adr[0]);
assign a2 = (adr[1] & ~adr[0]);
assign a3 = (adr[1] & adr[0]);
assign inbusL = (~ben | a0) ? inbus[7:0] : a1 ? inbus[15:8] : a2 ? inbus[23:16] : inbus[31:24];
assign outbusB0 = A[7:0];
assign outbusB1 = (ben & a1) ? A[7:0] : A[15:8];
assign outbusB2 = (ben & a2) ? A[7:0] : A[23:16];
assign outbusB3 = (ben & a3) ? A[7:0] : A[31:24];
assign inbusH = ~ben ? inbus[31:8] : 24'h0;
assign A = R[ira0];
assign B = R[irb];
assign C0 = R[irc];
assign C1 = q ? {{16{v}}, imm} : C0;
assign aluRes = ~op[3] ? ~op[2] ? ~op[1] ? ~op[0] ? q ? ~u ? {{16{v}}, imm} : {imm, 16'h0} : ~u ? C0 : ~v ? H : {N, Z, C, OV, 20'h0, 8'h58} : t3 : s3 : ~op[1] ? ~op[0] ? (B & C1) : (B & ~C1) : ~op[0] ? (B | C1) : (B ^ C1) : ~op[2] ? ~op[1] ? ~op[0] ? ((B + C) + (u & C)) : ((B - C1) - (u & C)) : ~op[0] ? product[31:0] : quotient : ~op[1] ? fsum : ~op[0] ? fprod : fquot;
assign regmux = Ldr ? {inbusH, inbusL} : (Br & v) ? {8'h0, nxpc, 2'h0} : aluRes;
assign s1 = (sc0 == 3) ? {w ? B[2:0] : {3{B[31]}}, B[31:3]} : (sc0 == 2) ? {w ? B[1:0] : {2{B[31]}}, B[31:2]} : (sc0 == 1) ? {w ? B[0] : B[31], B[31:1]} : B;
assign s2 = (sc1 == 3) ? {w ? s1[11:0] : {12{B[31]}}, s1[31:12]} : (sc1 == 2) ? {w ? s1[7:0] : {8{B[31]}}, s1[31:8]} : (sc1 == 1) ? {w ? s1[3:0] : {4{B[31]}}, s1[31:4]} : s1;
assign s3 = C1[4] ? {w ? s2[15:0] : {16{s2[31]}}, s2[31:16]} : s2;
assign t1 = (sc0 == 3) ? {B[28:0], 3'h0} : (sc0 == 2) ? {B[29:0], 2'h0} : (sc0 == 1) ? {B[30:0], 1'h0} : B;
assign t2 = (sc1 == 3) ? {t1[19:0], 12'h0} : (sc1 == 2) ? {t1[23:0], 8'h0} : (sc1 == 1) ? {t1[27:0], 4'h0} : t1;
assign t3 = C1[4] ? {t2[15:0], 16'h0} : t2;
assign Add = (~p & (op == 8));
assign Sub = (~p & (op == 9));
assign Mul = (~p & (op == 10));
assign Div = (~p & (op == 11));
assign Fadd = (~p & (op == 12));
assign Fsub = (~p & (op == 13));
assign Fmul = (~p & (op == 14));
assign Fdiv = (~p & (op == 15));
assign Ldr = ((p & ~q) & ~u);
assign Str = ((p & ~q) & u);
assign Br = (p & q);
always @ (posedge clk) begin PC <= pcmux;
IR <= stall ? IR : codebus;
N <= regwr ? regmux[31] : N;
Z <= regwr ? (regmux == 0) : Z;
C <= Add ? (((sb & sc) | ((~sa & ~sb) & sc)) | (((~sa & sb) & ~sc) & sa)) : Sub ? (((~sb & sc) | ((sa & ~sb) & ~sc)) | ((sa & sb) & sc)) : C;
OV <= Add ? (((sa & ~sb) & ~sc) | ((~sa & sb) & sc)) : Sub ? (((sa & ~sb) & sc) | ((~sa & sb) & ~sc)) : OV;
stall1 <= stallX ? stall1 : stallL;
PMsel <= (~rst | (pcmux[21:12] == 10'h3FF));
R[ira0] <= regwr ? regmux : A;
H <= Mul ? product[63:32] : Div ? remainder : H;
end
endmodule