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fixes #6255, add system.ashr arithmetic right shift (#8547)

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andri lim 2018-08-07 23:41:30 +07:00 • committed by Andreas Rumpf
commit 4d5cce9882
13 changed files with 95 additions and 12 deletions
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17
lib/system.nim
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@ -971,6 +971,23 @@ else:
proc `shl`*(x, y: int32): int32 {.magic: "ShlI", noSideEffect.}
proc `shl`*(x, y: int64): int64 {.magic: "ShlI", noSideEffect.}
when defined(nimAshr):
proc ashr*(x: int, y: SomeInteger): int {.magic: "AshrI", noSideEffect.}
proc ashr*(x: int8, y: SomeInteger): int8 {.magic: "AshrI", noSideEffect.}
proc ashr*(x: int16, y: SomeInteger): int16 {.magic: "AshrI", noSideEffect.}
proc ashr*(x: int32, y: SomeInteger): int32 {.magic: "AshrI", noSideEffect.}
proc ashr*(x: int64, y: SomeInteger): int64 {.magic: "AshrI", noSideEffect.}
## Shifts right by pushing copies of the leftmost bit in from the left,
## and let the rightmost bits fall off.
##
## .. code-block:: Nim
## 0b0001_0000'i8 shr 2 == 0b0000_0100'i8
## 0b1000_0000'i8 shr 8 == 0b1111_1111'i8
## 0b1000_0000'i8 shr 1 == 0b1100_0000'i8
else:
# used for bootstrapping the compiler
proc ashr*[T](x: T, y: SomeInteger): T = discard
proc `and`*(x, y: int): int {.magic: "BitandI", noSideEffect.}
proc `and`*(x, y: int8): int8 {.magic: "BitandI", noSideEffect.}
proc `and`*(x, y: int16): int16 {.magic: "BitandI", noSideEffect.}