JS: Corrected shift operators. Made casting between ints behave like C does.

1 files changed, 49 insertions, 9 deletions

diff --git a/compiler/jsgen.nim b/compiler/jsgen.nim
index c36f5a5a3..607b85924 100644
--- a/compiler/jsgen.nim
+++ b/compiler/jsgen.nim
@@ -264,7 +264,7 @@ const # magic checked op; magic unchecked op; checked op; unchecked op
     ["", "", "($1 - $2)", "($1 - $2)"], # SubF64
     ["", "", "($1 * $2)", "($1 * $2)"], # MulF64
     ["", "", "($1 / $2)", "($1 / $2)"], # DivF64
-    ["", "", "($1 >>> $2)", "($1 >>> $2)"], # ShrI
+    ["", "", "", ""], # ShrI
     ["", "", "($1 << $2)", "($1 << $2)"], # ShlI
     ["", "", "($1 & $2)", "($1 & $2)"], # BitandI
     ["", "", "($1 | $2)", "($1 | $2)"], # BitorI
@@ -344,19 +344,22 @@ proc binaryExpr(p: PProc, n: PNode, r: var TCompRes, magic, frmt: string) =
   r.res = frmt % [x.rdLoc, y.rdLoc]
   r.kind = resExpr
 
+proc unsignedTrimmer(size: BiggestInt): Rope =
+  case size
+    of 1: rope"& 0xff"
+    of 2: rope"& 0xffff"
+    of 4: rope">>> 0"
+    else: rope""
+
 proc binaryUintExpr(p: PProc, n: PNode, r: var TCompRes, op: string, reassign: bool = false) =
   var x, y: TCompRes
   gen(p, n.sons[1], x)
   gen(p, n.sons[2], y)
-  let trimmer = case n[1].typ.skipTypes(abstractRange).size
-    of 1: "& 0xff"
-    of 2: "& 0xffff"
-    of 4: ">>> 0"
-    else: ""
+  let trimmer = unsignedTrimmer(n[1].typ.skipTypes(abstractRange).size)
   if reassign:
-    r.res = "$1 = (($1 $2 $3) $4)" % [x.rdLoc, rope op, y.rdLoc, rope trimmer]
+    r.res = "$1 = (($1 $2 $3) $4)" % [x.rdLoc, rope op, y.rdLoc, trimmer]
   else:
-    r.res = "(($1 $2 $3) $4)" % [x.rdLoc, rope op, y.rdLoc, rope trimmer]
+    r.res = "(($1 $2 $3) $4)" % [x.rdLoc, rope op, y.rdLoc, trimmer]
 
 proc ternaryExpr(p: PProc, n: PNode, r: var TCompRes, magic, frmt: string) =
   var x, y, z: TCompRes
@@ -392,6 +395,12 @@ proc arith(p: PProc, n: PNode, r: var TCompRes, op: TMagic) =
   of mSubU: binaryUintExpr(p, n, r, "-")
   of mMulU: binaryUintExpr(p, n, r, "*")
   of mDivU: binaryUintExpr(p, n, r, "/")
+  of mShrI:
+    var x, y: TCompRes
+    gen(p, n.sons[1], x)
+    gen(p, n.sons[2], y)
+    let trimmer = unsignedTrimmer(n[1].typ.skipTypes(abstractRange).size)
+    r.res = "(($1 $2) >>> $3)" % [x.rdLoc, trimmer, y.rdLoc]
   else:
     arithAux(p, n, r, op, jsOps)
   r.kind = resExpr
@@ -1569,6 +1578,37 @@ proc genPragma(p: PProc, n: PNode) =
     of wEmit: genAsmOrEmitStmt(p, it.sons[1])
     else: discard
 
+proc genCast(p: PProc, n: PNode, r: var TCompRes) =
+  var dest = skipTypes(n.typ, abstractVarRange)
+  var src = skipTypes(n.sons[1].typ, abstractVarRange)
+  gen(p, n.sons[1], r)
+  if dest.kind == src.kind:
+    # no-op conversion
+    return
+  let toInt = (dest.kind in tyInt .. tyInt32)
+  let toUint = (dest.kind in tyUInt .. tyUInt32)
+  let fromInt = (src.kind in tyInt .. tyInt32)
+  let fromUint = (src.kind in tyUInt .. tyUInt32)
+
+  if toUint and (fromInt or fromUint):
+    let trimmer = unsignedTrimmer(dest.size)
+    r.res = "($1 $2)" % [r.res, trimmer]
+  elif toInt:
+    if fromInt:
+      let trimmer = unsignedTrimmer(dest.size)
+      r.res = "($1 $2)" % [r.res, trimmer]
+    elif fromUint:
+      if src.size == 4 and dest.size == 4:
+        r.res = "($1|0)" % [r.res]
+      else:
+        let trimmer = unsignedTrimmer(dest.size)
+        let minuend = case dest.size
+          of 1: "0xfe"
+          of 2: "0xfffe"
+          of 4: "0xfffffffe"
+          else: ""
+        r.res = "($1 - ($2 $3))" % [rope minuend, r.res, trimmer]
+
 proc gen(p: PProc, n: PNode, r: var TCompRes) =
   r.typ = etyNone
   r.kind = resNone
@@ -1630,7 +1670,7 @@ proc gen(p: PProc, n: PNode, r: var TCompRes) =
   of nkCheckedFieldExpr: genCheckedFieldAccess(p, n, r)
   of nkObjDownConv: gen(p, n.sons[0], r)
   of nkObjUpConv: upConv(p, n, r)
-  of nkCast: gen(p, n.sons[1], r)
+  of nkCast: genCast(p, n, r)
   of nkChckRangeF: genRangeChck(p, n, r, "chckRangeF")
   of nkChckRange64: genRangeChck(p, n, r, "chckRange64")
   of nkChckRange: genRangeChck(p, n, r, "chckRange")