Closed
Bug 586267
Opened 14 years ago
Closed 13 years ago
JM: Detect MUL overflow on ARM.
Categories
(Core :: JavaScript Engine, enhancement)
Tracking
()
RESOLVED
DUPLICATE
of bug 673314
People
(Reporter: jbramley, Assigned: jbramley)
Details
From jsop_binary:
----
#if defined(JS_CPU_ARM)
/* ARM cannot detect integer overflow with multiplication. */
|| op == JSOP_MUL
#endif /* JS_CPU_ARM */
----
It is possible using this sequence:
SMULL rLo, rHi, rA, rB
CMP rHi, rLo, ASR #31
The 32-bit result will be in rLo. rHi can be any scratch register. The only caveat is that the sequence sets the Z flag, not the V flag.
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Assignee | |
Updated•13 years ago
|
Status: ASSIGNED → RESOLVED
Closed: 13 years ago
Resolution: --- → DUPLICATE
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Description
•