OpenRISC 1000
l.div and l.divu do not set carry on divide by zero with Or1ksim #91
Closed jeremybennett opened this issue almost 14 years ago
jeremybennett commented almost 14 years ago
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The OR1200 spec requires l.div and l.divu to set the carry flag on divide by zero as required. This doesn't happen in Or1ksim.
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Reported in <em>Implementation and Verification of a CPU Subsystem for Multimode RF Transceivers</em> by Waqas Ahmed of the Royal Institute of Technology, Sweden.
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<p>
Jeremy
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jeremybennett was assigned almost 14 years ago
jeremybennett commented almost 14 years ago
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In testing another aspect of this bug appeared. On divide by zero l.div throws an illegal instruction exception, rather than a range exception.
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jeremybennett commented almost 14 years ago
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Fixed in top of tree. Scheduled for inclusion in Or1ksim 0.4.0rc2.
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Marking closed.
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Jeremy
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jeremybennett closed this almost 14 years ago
rherveille commented almost 14 years ago
Aha ... I was already wondering what exception was set during a divide by zero. So range expception is what should be used?
Which means a 'divide by zero' exception is the combination of 'range exception'+'carry' ??
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