diff options
Diffstat (limited to 'src/internal/abi/abi.go')
| -rw-r--r-- | src/internal/abi/abi.go | 45 |
1 files changed, 44 insertions, 1 deletions
diff --git a/src/internal/abi/abi.go b/src/internal/abi/abi.go index aaff9cece3..eadff248d9 100644 --- a/src/internal/abi/abi.go +++ b/src/internal/abi/abi.go @@ -4,7 +4,10 @@ package abi -import "unsafe" +import ( + "internal/goarch" + "unsafe" +) // RegArgs is a struct that has space for each argument // and return value register on the current architecture. @@ -33,6 +36,46 @@ type RegArgs struct { ReturnIsPtr IntArgRegBitmap } +// IntRegArgAddr returns a pointer inside of r.Ints[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) IntRegArgAddr(reg int, argSize uintptr) unsafe.Pointer { + if argSize > goarch.PtrSize || argSize == 0 || argSize&(argSize-1) != 0 { + panic("invalid argSize") + } + offset := uintptr(0) + if goarch.BigEndian { + offset = goarch.PtrSize - argSize + } + 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 |