Le 02/02/2025 à 13:46, Denis Kirjanov a écrit :
Looks like we have a typo in the do-while loop
while checking the loop condition. Fix it with the boolean OR
Are you sure it is a typo, not a feature ?
At the moment the generated code is:
6f4: 7f 89 48 38 and r9,r28,r9
6f8: 7f aa 50 38 and r10,r29,r10
6fc: 7d 29 53 79 or. r9,r9,r10
700: 40 82 ff bc bne 6bc <core99_usb_enable+0x1c0>
With your patch it now is:
6f8: 7f 89 48 38 and r9,r28,r9
6fc: 7f aa 50 38 and r10,r29,r10
700: 7d 29 53 78 or r9,r9,r10
...
708: 2f 89 00 00 cmpwi cr7,r9,0
70c: 40 9e ff b8 bne cr7,6c4 <core99_usb_enable+0x1c8>
So with your patch the code is doing exactly the same but is less optimal.
0 || 0 ==> 0
0 || !0 ==> 1
!0 || 0 ==> 1
!0 || !0 ==> 1
0 | 0 ==> 0
!0 | 0 ==> !0
0 | !0 ==> !0
!0 | !0 ==> !0
In both case it is only false when the two sides are 0 otherwise it is true.
Usually a logic OR does the same as a boolean OR but is more optimal.
Christophe
Signed-off-by: Denis Kirjanov <[email protected]>
---
arch/powerpc/platforms/powermac/feature.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/powerpc/platforms/powermac/feature.c
b/arch/powerpc/platforms/powermac/feature.c
index d3bcfe590384..9d929fbfc46b 100644
--- a/arch/powerpc/platforms/powermac/feature.c
+++ b/arch/powerpc/platforms/powermac/feature.c
@@ -1174,7 +1174,7 @@ core99_usb_enable(struct device_node *node, long param,
long value)
mdelay(1);
status0 = UN_IN(UNI_N_CLOCK_STOP_STATUS0);
status1 = UN_IN(UNI_N_CLOCK_STOP_STATUS1);
- } while ((status0 & test0) | (status1 & test1));
+ } while ((status0 & test0) || (status1 & test1));
LOCK(flags);
}
} else {
