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-rw-r--r--src/runtime/sys_linux_ppc64x.s23
1 files changed, 15 insertions, 8 deletions
diff --git a/src/runtime/sys_linux_ppc64x.s b/src/runtime/sys_linux_ppc64x.s
index 01d6c85597..b86a820ab2 100644
--- a/src/runtime/sys_linux_ppc64x.s
+++ b/src/runtime/sys_linux_ppc64x.s
@@ -119,16 +119,23 @@ TEXT runtimeĀ·pipe2(SB),NOSPLIT|NOFRAME,$0-20
MOVW R3, errno+16(FP)
RET
+// func usleep(usec uint32)
TEXT runtimeĀ·usleep(SB),NOSPLIT,$16-4
MOVW usec+0(FP), R3
- MOVD R3, R5
- MOVW $1000000, R4
- DIVD R4, R3
- MOVD R3, 8(R1)
- MOVW $1000, R4
- MULLD R3, R4
- SUB R4, R5
- MOVD R5, 16(R1)
+
+ // Use magic constant 0x8637bd06 and shift right 51
+ // to perform usec/1000000.
+ ORIS $0x8637, R0, R4 // Note, R0 always contains 0 here.
+ OR $0xbd06, R4, R4
+ MULLD R3, R4, R4 // Convert usec to S.
+ SRD $51, R4, R4
+ MOVD R4, 8(R1) // Store to tv_sec
+
+ MOVD $1000000, R5
+ MULLW R4, R5, R5 // Convert tv_sec back into uS
+ SUB R5, R3, R5 // Compute remainder uS.
+ MULLD $1000, R5, R5 // Convert to nsec
+ MOVD R5, 16(R1) // Store to tv_nsec
// nanosleep(&ts, 0)
ADD $8, R1, R3