Try to align the native code to the next 8 byte boundary #899
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| NativeCodePage = mapper.MapWriteable(codeLength + 7); | ||
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| // Round to 8 byte boundary | ||
| var start = new IntPtr(((NativeCodePage.ToInt64() + 7) >> 3) << 3); |
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>> 3) << 3) can be replaced with & ~0x7L
IMHO, even better to write a generic align function (and unit test it)
| Marshal.Copy(NativeCode.Active.Code, 0, NativeCodePage, codeLength); | ||
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| // Request 7 bytes more than required such that we can align to an 8 byte boundary on ARM | ||
| NativeCodePage = mapper.MapWriteable(codeLength + 7); |
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mmap will return minimum a full page, and pages are typically 4096-byte-aligned (certainly more than 8-byte aligned). Add some logging to make sure, but I don't expect your changes are actually doing anything.
After the bx lr you might need a nop? I don't know this ISA myself, but it's not uncommon in architectures with branch prediction (i.e. basically all of them) that it'll unconditionally run an opcode right after a branch.
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https://community.arm.com/developer/ip-products/processors/f/cortex-m-forum/7154/alignment-in-arm
Looks like you need 16-byte-aligned if it's 64-bit ARM. So your Return1 is not properly aligned.
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The older RPis are 32bit, though, so this (8 byte alignment) can't be the current issue.
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You mentioned compiling on the raspberry pi was slow. You can compile the C# dll on any platform -- as long as you set the |
What does this implement/fix? Explain your changes.
Aligns the ARM code to the next 8 byte boundary.
Does this close any currently open issues?
Maybe #898