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Ayke van Laethem
4f1b69827d
The reflect package needs to know the endianness of the system in a few places. Before this patch, it assumed little-endian systems. But with GOARCH=mips we now have a big-endian system which also needs to be supported. So this patch fixes the reflect package to work on big-endian systems. Also, I've updated the tests for MIPS: instead of running the little-endian tests, I've changed it to run the big-endian tests instead. The two are very similar except for endianness so this should be fine. To be sure we won't accidentally break little-endian support, I've kept a single MIPS little-endian test (the CGo test, which doesn't yet work on big-endian systems anyway).
36 lines
1.0 KiB
Go
36 lines
1.0 KiB
Go
//go:build !mips
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package reflect
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import "unsafe"
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// loadValue loads a value that may or may not be word-aligned. The number of
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// bytes given in size are loaded. The biggest possible size it can load is that
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// of an uintptr.
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func loadValue(ptr unsafe.Pointer, size uintptr) uintptr {
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loadedValue := uintptr(0)
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shift := uintptr(0)
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for i := uintptr(0); i < size; i++ {
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loadedValue |= uintptr(*(*byte)(ptr)) << shift
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shift += 8
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ptr = unsafe.Add(ptr, 1)
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}
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return loadedValue
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}
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// storeValue is the inverse of loadValue. It stores a value to a pointer that
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// doesn't need to be aligned.
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func storeValue(ptr unsafe.Pointer, size, value uintptr) {
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for i := uintptr(0); i < size; i++ {
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*(*byte)(ptr) = byte(value)
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ptr = unsafe.Add(ptr, 1)
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value >>= 8
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}
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}
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// maskAndShift cuts out a part of a uintptr. Note that the offset may not be 0.
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func maskAndShift(value, offset, size uintptr) uintptr {
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mask := ^uintptr(0) >> ((unsafe.Sizeof(uintptr(0)) - size) * 8)
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return (uintptr(value) >> (offset * 8)) & mask
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}
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