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add support cast[integer] in VM

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Parashurama
2017-08-23 13:42:40 +02:00
committed by Andreas Rumpf
parent 3073f08e48
commit 41472f0e28
1 changed files with 45 additions and 2 deletions
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47
compiler/vmgen.nim
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@@ -30,7 +30,7 @@
import
strutils, ast, astalgo, types, msgs, renderer, vmdef,
trees, intsets, rodread, magicsys, options, lowerings
import platform
from os import splitFile
when hasFFI:
@@ -761,6 +761,49 @@ proc genCard(c: PCtx; n: PNode; dest: var TDest) =
c.gABC(n, opcCard, dest, tmp)
c.freeTemp(tmp)
proc genIntCast(c: PCtx; n: PNode; dest: var TDest) =
const allowedIntegers = {tyInt..tyInt64, tyUInt..tyUInt64, tyChar}
var signedIntegers = {tyInt8..tyInt32}
var unsignedIntegers = {tyUInt8..tyUInt32, tyChar}
let src = n.sons[1].typ.skipTypes(abstractRange)#.kind
let dst = n.sons[0].typ.skipTypes(abstractRange)#.kind
let src_size = src.getSize
if platform.intSize < 8:
signedIntegers.incl(tyInt)
unsignedIntegers.incl(tyUInt)
if src_size == dst.getSize and src.kind in allowedIntegers and
dst.kind in allowedIntegers:
let tmp = c.genx(n.sons[1])
var tmp2 = c.getTemp(n.sons[1].typ)
let tmp3 = c.getTemp(n.sons[1].typ)
if dest < 0: dest = c.getTemp(n[0].typ)
proc mkIntLit(ival: int): int =
result = genLiteral(c, newIntTypeNode(nkIntLit, ival, getSysType(tyInt)))
if src.kind in unsignedIntegers and dst.kind in signedIntegers:
# cast unsigned to signed integer of same size
# signedVal = (unsignedVal xor offset) -% offset
let offset = 1 shl (src_size * 8 - 1)
c.gABx(n, opcLdConst, tmp2, mkIntLit(offset))
c.gABC(n, opcBitxorInt, tmp3, tmp, tmp2)
c.gABC(n, opcSubInt, dest, tmp3, tmp2)
elif src.kind in signedIntegers and dst.kind in unsignedIntegers:
# cast signed to unsigned integer of same size
# unsignedVal = (offset +% signedVal +% 1) and offset
let offset = (1 shl (src_size * 8)) - 1
c.gABx(n, opcLdConst, tmp2, mkIntLit(offset))
c.gABx(n, opcLdConst, dest, mkIntLit(offset+1))
c.gABC(n, opcAddu, tmp3, tmp, dest)
c.gABC(n, opcNarrowU, tmp3, TRegister(src_size*8))
c.gABC(n, opcBitandInt, dest, tmp3, tmp2)
else:
c.gABC(n, opcAsgnInt, dest, tmp)
c.freeTemp(tmp)
c.freeTemp(tmp2)
c.freeTemp(tmp3)
else:
globalError(n.info, errGenerated, "VM is only allowed to 'cast' between integers of same size")
proc genMagic(c: PCtx; n: PNode; dest: var TDest; m: TMagic) =
case m
of mAnd: c.genAndOr(n, opcFJmp, dest)
@@ -1844,7 +1887,7 @@ proc gen(c: PCtx; n: PNode; dest: var TDest; flags: TGenFlags = {}) =
if allowCast in c.features:
genConv(c, n, n.sons[1], dest, opcCast)
else:
globalError(n.info, errGenerated, "VM is not allowed to 'cast'")
genIntCast(c, n, dest)
of nkTypeOfExpr:
genTypeLit(c, n.typ, dest)
of nkComesFrom: