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VM can now cast integer type arbitrarily. (#11459) [feature]

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Arne Döring 2019-06-10 19:58:11 +02:00 • committed by Andreas Rumpf
commit 94177f7357
2 changed files with 143 additions and 31 deletions
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46
compiler/vmgen.nim
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@ -813,44 +813,28 @@ proc genCard(c: PCtx; n: PNode; dest: var TDest) =
proc genCastIntFloat(c: PCtx; n: PNode; dest: var TDest) =
const allowedIntegers = {tyInt..tyInt64, tyUInt..tyUInt64, tyChar}
var signedIntegers = {tyInt8..tyInt32}
var unsignedIntegers = {tyUInt8..tyUInt32, tyChar}
var signedIntegers = {tyInt..tyInt64}
var unsignedIntegers = {tyUInt..tyUInt64, tyChar}
let src = n.sons[1].typ.skipTypes(abstractRange)#.kind
let dst = n.sons[0].typ.skipTypes(abstractRange)#.kind
let src_size = getSize(c.config, src)
let dst_size = getSize(c.config, dst)
if c.config.target.intSize < 8:
signedIntegers.incl(tyInt)
unsignedIntegers.incl(tyUInt)
if src_size == dst_size and src.kind in allowedIntegers and
dst.kind in allowedIntegers:
if 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(c.graph, n.info, 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.gABC(n, opcAsgnInt, dest, tmp)
if dst_size != sizeof(BiggestInt): # don't do anything on biggest int types
if dst.kind in signedIntegers: # we need to do sign extensions
if dst_size <= src_size:
# Sign extension can be omitted when the size increases.
c.gABC(n, opcSignExtend, dest, TRegister(dst_size*8))
elif dst.kind in unsignedIntegers:
if src.kind in signedIntegers or dst_size < src_size:
# Cast from signed to unsigned always needs narrowing. Cast
# from unsigned to unsigned only needs narrowing when target
# is smaller than source.
c.gABC(n, opcNarrowU, dest, TRegister(dst_size*8))
c.freeTemp(tmp)
c.freeTemp(tmp2)
c.freeTemp(tmp3)
elif src_size == dst_size and src.kind in allowedIntegers and
dst.kind in {tyFloat, tyFloat32, tyFloat64}:
let tmp = c.genx(n[1])