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author Vas Crabb <vas@vastheman.com>2017-12-02 23:41:43 +1100
committer Vas Crabb <vas@vastheman.com>2017-12-02 23:44:19 +1100
commit843cf2982eb245531d454d788821230ca000fb7e (patch)
tree626c4ce66c81549d9879f23d9ebcee0b32d2b339 /src/osd/eigccx86.h
parent51c06e670fadc0172268149fee689a54ee06e644 (diff)
allow compiler a little more optimisation leeway in x86 count_leading_* (nw)
Diffstat (limited to 'src/osd/eigccx86.h')
-rw-r--r--src/osd/eigccx86.h10
1 files changed, 4 insertions, 6 deletions
diff --git a/src/osd/eigccx86.h b/src/osd/eigccx86.h
index b67b646451e..b3831d21524 100644
--- a/src/osd/eigccx86.h
+++ b/src/osd/eigccx86.h
@@ -474,13 +474,12 @@ _count_leading_zeros(uint32_t value)
__asm__ (
" bsrl %[value], %[result] ;"
" cmovzl %[bias], %[result] ;"
- " xorl $31, %[result] ;"
: [result] "=&r" (result) // result can be in any register
: [value] "rm" (value) // 'value' can be register or memory
- , [bias] "rm" (uint32_t(63)) // 'bias' can be register or memory
+ , [bias] "rm" (~uint32_t(0)) // 'bias' can be register or memory
: "cc" // clobbers condition codes
);
- return result;
+ return 31U - result;
}
@@ -497,13 +496,12 @@ _count_leading_ones(uint32_t value)
__asm__ (
" bsrl %[value], %[result] ;"
" cmovzl %[bias], %[result] ;"
- " xorl $31, %[result] ;"
: [result] "=&r" (result) // result can be in any register
: [value] "rm" (~value) // 'value' can be register or memory
- , [bias] "rm" (uint32_t(63)) // 'bias' can be register or memory
+ , [bias] "rm" (~uint32_t(0)) // 'bias' can be register or memory
: "cc" // clobbers condition codes
);
- return result;
+ return 31U - result;
}
#endif // MAME_OSD_EIGCCX86_H