183 lines
7.3 KiB
Systemverilog
183 lines
7.3 KiB
Systemverilog
// DESCRIPTION: Verilator: Verilog Test module
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//
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// Test inline pre/post increment/decrement operators, including
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// inside logical operators (&&, ||) with short-circuit semantics.
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//
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// This file ONLY is placed under the Creative Commons Public Domain.
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// SPDX-FileCopyrightText: 2026 Wilson Snyder
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// SPDX-License-Identifier: CC0-1.0
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// verilog_format: off
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`define stop $stop
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`define checkh(gotv,expv) do if ((gotv) !== (expv)) begin $write("%%Error: %s:%0d: got=%0x exp=%0x (%s !== %s)\n", `__FILE__,`__LINE__, (gotv), (expv), `"gotv`", `"expv`"); `stop; end while(0);
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`define checks(gotv,expv) do if ((gotv) != (expv)) begin $write("%%Error: %s:%0d: got='%s' exp='%s'\n", `__FILE__,`__LINE__, (gotv), (expv)); `stop; end while(0);
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// verilog_format: on
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module t;
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integer a, b, c;
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reg cond;
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int side;
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// Impure (side-effecting) function for use as a short-circuit LHS
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function automatic int bump();
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side = side + 1;
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return 1;
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endfunction
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// ++/-- in && / || inside a function/task exercises the function-local temp
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function automatic int f_and(int x);
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if (x > 0 && x++ < 100) ;
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return x;
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endfunction
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function automatic int f_or(int x);
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if (x > 0 || x++ < 100) ;
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return x;
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endfunction
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// LHS reads the gated variable; must see the pre-increment value exactly once
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function automatic int f_single(int x);
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int taken = 0;
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if (x == 4 && x++ < 100) taken = 1;
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return taken * 1000 + x;
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endfunction
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initial begin
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// ---- Basic post/pre increment/decrement ----
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a = 5; b = a++; `checkh(b, 5); `checkh(a, 6);
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a = 5; b = ++a; `checkh(a, 6); `checkh(b, 6);
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a = 10; b = 5; b = a++ + b; `checkh(b, 15); `checkh(a, 11);
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a = 10; b = 5; b = ++a + b; `checkh(b, 16); `checkh(a, 11);
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a = 7; b = a++ * 2; `checkh(b, 14); `checkh(a, 8);
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a = 7; b = ++a * 2; `checkh(b, 16); `checkh(a, 8);
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a = 3; b = 4; c = a++ + b++; `checkh(c, 7); `checkh(a, 4); `checkh(b, 5);
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a = 3; b = 4; c = ++a + ++b; `checkh(c, 9); `checkh(a, 4); `checkh(b, 5);
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a = 10; b = 3; c = a++ - b--; `checkh(c, 7); `checkh(a, 11); `checkh(b, 2);
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a = 5; b = 5; b = a--; `checkh(b, 5); `checkh(a, 4);
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a = 5; b = --a; `checkh(b, 4); `checkh(a, 4);
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// ---- Post-inc in shift (5 << 5 = 160) ----
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a = 5; b = 5; b = b << a++; `checkh(b, 160); `checkh(a, 6);
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// ---- Post-inc in paren expr ----
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a = 2; b = (a++ + 1) * 3; `checkh(b, 9); `checkh(a, 3);
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// ---- Post-inc in while with && (constant) ----
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a = 0; while (1 && a++ < 3) begin end `checkh(a, 4);
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// ---- Post-inc in while with && (variable cond, non-short-circuit) ----
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cond = 1; a = 0; while (cond && a++ < 3) begin end `checkh(a, 4);
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// ---- Post-inc in while with && (variable cond, short-circuit) ----
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cond = 0; a = 0; while (cond && a++ < 3) begin end `checkh(a, 0);
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// ---- Post-inc in while with || ----
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a = 0; while (0 || a++ < 3) begin end `checkh(a, 4);
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// ---- && short-circuit ----
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a = 0; if (0 && a++ < 3) begin end `checkh(a, 0);
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// ---- && non-short-circuit ----
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a = 0; if (1 && a++ < 5) begin end `checkh(a, 1);
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// ---- || non-short-circuit ----
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a = 0; if (0 || a++ < 5) begin end `checkh(a, 1);
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// ---- || short-circuit ----
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a = 0; if (1 || a++ < 5) begin end `checkh(a, 0);
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// ---- Pre-inc with && ----
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a = 0; if (1 && ++a < 5) begin end `checkh(a, 1);
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// ---- Pre-inc short-circuit ----
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a = 0; if (0 && ++a < 5) begin end `checkh(a, 0);
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// ---- Pre-inc with || ----
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a = 0; if (0 || ++a < 5) begin end `checkh(a, 1);
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a = 0; if (1 || ++a < 5) begin end `checkh(a, 0);
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// ---- Nested && chain ----
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a = 0; if (1 && 1 && a++ < 5) begin end `checkh(a, 1);
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// ---- Post-dec with && ----
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a = 5; if (1 && a-- > 0) begin end `checkh(a, 4);
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// ---- Pre-dec with && short-circuit ----
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a = 5; if (0 && --a > 0) begin end `checkh(a, 5);
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// ---- Post-dec with || ----
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a = 5; if (0 || a-- > 0) begin end `checkh(a, 4);
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a = 5; if (1 || a-- > 0) begin end `checkh(a, 5);
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// ---- Pre-dec with || ----
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a = 5; if (0 || --a > 0) begin end `checkh(a, 4);
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// ---- Multiple increments in && chain ----
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a = 0; b = 0;
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if (1 && a++ < 5 && b++ < 5) begin end
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`checkh(a, 1); `checkh(b, 1);
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// ---- Post-inc on left side of && ----
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a = 0; if (a++ < 5 && 1) begin end `checkh(a, 1);
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// ---- Post-inc on left side of || ----
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a = 0; if (a++ < 5 || 0) begin end `checkh(a, 1);
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// ---- Pre-inc on left side of || ----
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a = 0; if (++a < 5 || 0) begin end `checkh(a, 1);
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// ---- Mixed && and || with post-inc ----
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a = 0; b = 0;
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if (1 && a++ < 5 || b++ < 5) begin end
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`checkh(a, 1); `checkh(b, 0);
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a = 0; b = 0;
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if (0 && a++ < 5 || b++ < 5) begin end
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`checkh(a, 0); `checkh(b, 1);
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// ---- Deep nesting (3 levels &&) ----
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a = 0; b = 0; c = 0;
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if (1 && 1 && a++ < 5 && b++ < 5 && c++ < 5) begin end
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`checkh(a, 1); `checkh(b, 1); `checkh(c, 1);
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a = 0; b = 0; c = 0;
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if (1 && 0 && a++ < 5 && b++ < 5 && c++ < 5) begin end
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`checkh(a, 0); `checkh(b, 0); `checkh(c, 0);
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// ---- LHS reads variable that gated RHS ++/-- writes (single-eval) ----
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a = 4; if (a == 4 && a++ < 10) begin end `checkh(a, 5);
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a = 6; if (a == 4 && a++ < 10) begin end `checkh(a, 6);
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a = 0; if (a < 1 && a++ < 5) begin end `checkh(a, 1);
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a = 5; if (a > 0 && a-- > 0) begin end `checkh(a, 4);
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a = 4; if (a == 4 && ++a < 10) begin end `checkh(a, 5);
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// ---- || mirror: LHS reads variable that gated RHS modifies ----
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a = 4; if (a != 4 || a++ < 10) begin end `checkh(a, 5);
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a = 6; if (a != 4 || a++ < 10) begin end `checkh(a, 6);
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// ---- Nested gate: inner && with non-const LHS inside an outer gate ----
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a = 4; if (a == 4 && (a < 10 && a++ < 20)) begin end `checkh(a, 5);
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a = 20; if (a == 20 && (a < 10 && a++ < 30)) begin end `checkh(a, 20);
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a = 0; if (a == 4 && (a < 10 && a++ < 20)) begin end `checkh(a, 0);
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// ---- ++/-- in && / || inside a function (function-local temp) ----
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`checkh(f_and(5), 6); // 5>0 true, post-inc runs -> 6
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`checkh(f_and(0), 0); // 0>0 false, short-circuit -> unchanged
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`checkh(f_or(5), 5); // 5>0 true, short-circuit -> unchanged
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`checkh(f_or(0), 1); // 0>0 false, post-inc runs -> 1
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`checkh(f_single(4), 1005); // 4==4 (once) && 4<100 -> taken=1, x=5
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`checkh(f_single(6), 6); // 6==4 false, short-circuit -> taken=0, x=6
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// ---- Impure (side-effecting) LHS must be evaluated exactly once ----
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side = 0; a = 0; if (bump() > 0 && a++ < 5) begin end `checkh(side, 1); `checkh(a, 1);
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side = 0; a = 0; if (bump() < 0 && a++ < 5) begin end `checkh(side, 1); `checkh(a, 0);
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// ---- ++/-- on LHS, side-effecting function on opposite (RHS) side ----
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side = 0; a = 0; if (a++ < 5 && bump() > 0) begin end `checkh(a, 1); `checkh(side, 1);
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side = 0; a = 0; if (a++ > 5 && bump() > 0) begin end `checkh(a, 1); `checkh(side, 0);
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side = 0; a = 0; if (a++ > 5 || bump() > 0) begin end `checkh(a, 1); `checkh(side, 1);
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side = 0; a = 0; if (a++ < 5 || bump() > 0) begin end `checkh(a, 1); `checkh(side, 0);
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$write("*-* All Finished *-*\n");
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$finish;
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end
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endmodule
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