FPU bug on mixed-endian CPUs \ VOGONS

FPU bug on mixed-endian CPUs

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First post, by M-HT

Posted on 2010-09-06, 09:16

M-HT Offline

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Some ARM CPUs use little-endian byte ordering for integers, but use big-endian word ordering for double floating-point numbers.
This causes a bug in some FPU instructions, because dosbox assumes that byte ordering for integers and word ordering for doubles is the same.

Proposed fix is in the attachment.

Reply 1 of 1, by wd

Posted on 2010-09-06, 12:11

wd Offline

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Some ARM CPUs use little-endian byte ordering for integers, but use big-endian word ordering for double floating-point numbers.

So they were like "big endian was fun to piss off x86, now mix things to get
even more fun out of this" and did that intentionally? Nice 😀

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