time: faster Nanoseconds call
runtime knows how to get the time of day
without allocating memory.
R=golang-dev, dsymonds, dave, hectorchu, r, cw
CC=golang-dev
https://golang.org/cl/5297078
diff --git a/src/pkg/runtime/linux/386/sys.s b/src/pkg/runtime/linux/386/sys.s
index 1b4f649..97d9d5e 100644
--- a/src/pkg/runtime/linux/386/sys.s
+++ b/src/pkg/runtime/linux/386/sys.s
@@ -95,21 +95,28 @@
CALL *runtime·_vdso(SB)
RET
-TEXT runtime·gettime(SB), 7, $32
+// int64 nanotime(void) so really
+// void nanotime(int64 *nsec)
+TEXT runtime·nanotime(SB), 7, $32
MOVL $78, AX // syscall - gettimeofday
LEAL 8(SP), BX
MOVL $0, CX
MOVL $0, DX
CALL *runtime·_vdso(SB)
-
- MOVL 8(SP), BX // sec
- MOVL sec+0(FP), DI
- MOVL BX, (DI)
- MOVL $0, 4(DI) // zero extend 32 -> 64 bits
-
+ MOVL 8(SP), AX // sec
MOVL 12(SP), BX // usec
- MOVL usec+4(FP), DI
- MOVL BX, (DI)
+
+ // sec is in AX, usec in BX
+ // convert to DX:AX nsec
+ MOVL $1000000000, CX
+ MULL CX
+ IMULL $1000, BX
+ ADDL BX, AX
+ ADCL $0, DX
+
+ MOVL ret+0(FP), DI
+ MOVL AX, 0(DI)
+ MOVL DX, 4(DI)
RET
TEXT runtime·rt_sigaction(SB),7,$0
diff --git a/src/pkg/runtime/linux/amd64/sys.s b/src/pkg/runtime/linux/amd64/sys.s
index 3174af2..227c8e6 100644
--- a/src/pkg/runtime/linux/amd64/sys.s
+++ b/src/pkg/runtime/linux/amd64/sys.s
@@ -93,19 +93,19 @@
SYSCALL
RET
-TEXT runtime·gettime(SB), 7, $32
+TEXT runtime·nanotime(SB), 7, $32
LEAQ 8(SP), DI
MOVQ $0, SI
MOVQ $0xffffffffff600000, AX
CALL AX
+ MOVQ 8(SP), AX // sec
+ MOVL 16(SP), DX // usec
- MOVQ 8(SP), BX // sec
- MOVQ sec+0(FP), DI
- MOVQ BX, (DI)
-
- MOVL 16(SP), BX // usec
- MOVQ usec+8(FP), DI
- MOVL BX, (DI)
+ // sec is in AX, usec in DX
+ // return nsec in AX
+ IMULQ $1000000000, AX
+ IMULQ $1000, DX
+ ADDQ DX, AX
RET
TEXT runtime·rt_sigaction(SB),7,$0-32
diff --git a/src/pkg/runtime/linux/arm/sys.s b/src/pkg/runtime/linux/arm/sys.s
index 764e779..45da858 100644
--- a/src/pkg/runtime/linux/arm/sys.s
+++ b/src/pkg/runtime/linux/arm/sys.s
@@ -127,14 +127,14 @@
SWI $0
RET
-TEXT runtime·gettime(SB),7,$32
+// int64 nanotime(void) so really
+// void nanotime(int64 *nsec)
+TEXT runtime·nanotime(SB),7,$32
/* dummy version - return 0,0 */
MOVW $0, R1
MOVW 0(FP), R0
MOVW R1, 0(R0)
MOVW R1, 4(R0)
- MOVW 4(FP), R0
- MOVW R1, 0(R0)
/*
attempt at real version - seg faults
