Make '%' operator resemble (strange) JS semantics

Author: dcodeIO

src/compiler.ts

@@ -3271,74 +3271,50 @@ export class Compiler extends DiagnosticEmitter {
  expr = module.createBinary(BinaryOp.RemU64, leftExpr, rightExpr);
  break;
  }
-
- // FIXME: JS floating-point '%' is neither a proper modulo nor remainder
- // for now, there is f64/f32.mod/rem with C semantics
-
- // case TypeKind.F32: {
- // let remInstance = this.f32RemInstance;
- // if (!remInstance) {
- // let remNamespace = this.program.elementsLookup.get("f32");
- // if (!remNamespace) {
- // this.error(
- // DiagnosticCode.Cannot_find_name_0,
- // expression.range, "f32"
- // );
- // expr = module.createUnreachable();
- // break;
- // }
- // let remPrototype = remNamespace.members ? remNamespace.members.get("rem") : null;
- // if (!remPrototype) {
- // this.error(
- // DiagnosticCode.Cannot_find_name_0,
- // expression.range, "f32.rem"
- // );
- // expr = module.createUnreachable();
- // break;
- // }
- // assert(remPrototype.kind == ElementKind.FUNCTION_PROTOTYPE);
- // this.f32RemInstance = remInstance = (<FunctionPrototype>remPrototype).resolve();
- // }
- // if (!(remInstance && this.compileFunction(remInstance))) {
- // expr = module.createUnreachable();
- // } else {
- // expr = this.makeCallDirect(remInstance, [ leftExpr, rightExpr ]);
- // }
- // break;
- // }
-
- // case TypeKind.F64: {
- // let remInstance = this.f64RemInstance;
- // if (!remInstance) {
- // let remNamespace = this.program.elementsLookup.get("f64");
- // if (!remNamespace) {
- // this.error(
- // DiagnosticCode.Cannot_find_name_0,
- // expression.range, "f64"
- // );
- // expr = module.createUnreachable();
- // break;
- // }
- // let remPrototype = remNamespace.members ? remNamespace.members.get("rem") : null;
- // if (!remPrototype) {
- // this.error(
- // DiagnosticCode.Cannot_find_name_0,
- // expression.range, "f64.rem"
- // );
- // expr = module.createUnreachable();
- // break;
- // }
- // assert(remPrototype.kind == ElementKind.FUNCTION_PROTOTYPE);
- // this.f64RemInstance = remInstance = (<FunctionPrototype>remPrototype).resolve();
- // }
- // if (!(remInstance && this.compileFunction(remInstance))) {
- // expr = module.createUnreachable();
- // } else {
- // expr = this.makeCallDirect(remInstance, [ leftExpr, rightExpr ]);
- // }
- // break;
- // }
-
+ case TypeKind.F32: {
+ let remInstance = this.f32RemInstance;
+ if (!remInstance) {
+ let remPrototype = this.program.elementsLookup.get("jsremf");
+ if (!remPrototype) {
+ this.error(
+ DiagnosticCode.Cannot_find_name_0,
+ expression.range, "jsremf"
+ );
+ expr = module.createUnreachable();
+ break;
+ }
+ assert(remPrototype.kind == ElementKind.FUNCTION_PROTOTYPE);
+ this.f32RemInstance = remInstance = (<FunctionPrototype>remPrototype).resolve();
+ }
+ if (!(remInstance && this.compileFunction(remInstance))) {
+ expr = module.createUnreachable();
+ } else {
+ expr = this.makeCallDirect(remInstance, [ leftExpr, rightExpr ]);
+ }
+ break;
+ }
+ case TypeKind.F64: {
+ let remInstance = this.f64RemInstance;
+ if (!remInstance) {
+ let remPrototype = this.program.elementsLookup.get("jsrem");
+ if (!remPrototype) {
+ this.error(
+ DiagnosticCode.Cannot_find_name_0,
+ expression.range, "jsrem"
+ );
+ expr = module.createUnreachable();
+ break;
+ }
+ assert(remPrototype.kind == ElementKind.FUNCTION_PROTOTYPE);
+ this.f64RemInstance = remInstance = (<FunctionPrototype>remPrototype).resolve();
+ }
+ if (!(remInstance && this.compileFunction(remInstance))) {
+ expr = module.createUnreachable();
+ } else {
+ expr = this.makeCallDirect(remInstance, [ leftExpr, rightExpr ]);
+ }
+ break;
+ }
  default: {
  assert(false);
  this.error(

std/assembly/builtins.ts

@@ -172,3 +172,13 @@ export namespace f64 {
 export declare const HEAP_BASE: usize;
 
 export declare function start(): void;
+
+/** @internal */
+export function jsrem(x: f64, y: f64): f64 {
+ return copysign<f64>(NativeMath.mod(abs<f64>(x), abs<f64>(y)), x);
+}
+
+/** @internal */
+export function jsremf(x: f32, y: f32): f32 {
+ return copysign<f32>(NativeMathf.mod(abs<f32>(x), abs<f32>(y)), x);
+}

tests/compiler.js

@@ -118,7 +118,8 @@ tests.forEach(filename => {
  externalFunction: function() { },
  externalConstant: 1,
  logi: function(i) { console.log("logi: " + i); },
- logf: function(f) { console.log("logf: " + f); }
+ logf: function(f) { console.log("logf: " + f); },
+ jsrem: function(a, b) { return a % b; }
  },
  my: {
  externalFunction: function() { },