diff options
Diffstat (limited to 'src/internal/abi/abi.go')
| -rw-r--r-- | src/internal/abi/abi.go | 28 |
1 files changed, 8 insertions, 20 deletions
diff --git a/src/internal/abi/abi.go b/src/internal/abi/abi.go index eadff248d99..46dc593bd7e 100644 --- a/src/internal/abi/abi.go +++ b/src/internal/abi/abi.go @@ -19,6 +19,14 @@ import ( // when it may not be safe to keep them only in the integer // register space otherwise. type RegArgs struct { + // Values in these slots should be precisely the bit-by-bit + // representation of how they would appear in a register. + // + // This means that on big endian arches, integer values should + // be in the top bits of the slot. Floats are usually just + // directly represented, but some architectures treat narrow + // width floating point values specially (e.g. they're promoted + // first, or they need to be NaN-boxed). Ints [IntArgRegs]uintptr // untyped integer registers Floats [FloatArgRegs]uint64 // untyped float registers @@ -56,26 +64,6 @@ func (r *RegArgs) IntRegArgAddr(reg int, argSize uintptr) unsafe.Pointer { return unsafe.Pointer(uintptr(unsafe.Pointer(&r.Ints[reg])) + offset) } -// FloatRegArgAddr returns a pointer inside of r.Floats[reg] that is appropriately -// offset for an argument of size argSize. -// -// argSize must be non-zero, fit in a register, and a power-of-two. -// -// This method is a helper for dealing with the endianness of different CPU -// architectures, since sub-word-sized arguments in big endian architectures -// need to be "aligned" to the upper edge of the register to be interpreted -// by the CPU correctly. -func (r *RegArgs) FloatRegArgAddr(reg int, argSize uintptr) unsafe.Pointer { - if argSize > EffectiveFloatRegSize || argSize == 0 || argSize&(argSize-1) != 0 { - panic("invalid argSize") - } - offset := uintptr(0) - if goarch.BigEndian { - offset = EffectiveFloatRegSize - argSize - } - return unsafe.Pointer(uintptr(unsafe.Pointer(&r.Floats[reg])) + offset) -} - // IntArgRegBitmap is a bitmap large enough to hold one bit per // integer argument/return register. type IntArgRegBitmap [(IntArgRegs + 7) / 8]uint8 |