runtime: implement time.now in assembly on plan9, solaris, windows
These all used a C implementation that contained 64-bit divide by 1000000000.
On 32-bit systems that ends up in the 64-bit C divide support, which makes
other calls and ends up using a fair amount of stack. We could convert them
to Go but then they'd still end up in software 64-bit divide code. That would
be okay, because Go code can split the stack, but it's still unnecessary.
Write time·now in assembly, just like on all the other systems, and use the
actual hardware support for 64/32 -> 64/32 division. This cuts the software
routines out entirely.
The actual code to do the division is copied and pasted from the sys_darwin_*.s files.
LGTM=alex.brainman
R=golang-codereviews, alex.brainman
CC=aram, golang-codereviews, iant, khr, r
https://golang.org/cl/136300043
diff --git a/src/pkg/runtime/os_plan9.c b/src/pkg/runtime/os_plan9.c
index f824710..853f3ef 100644
--- a/src/pkg/runtime/os_plan9.c
+++ b/src/pkg/runtime/os_plan9.c
@@ -162,19 +162,6 @@
#pragma textflag NOSPLIT
void
-time·now(int64 sec, int32 nsec)
-{
- int64 ns;
-
- ns = runtime·nanotime();
- sec = ns / 1000000000LL;
- nsec = ns - sec * 1000000000LL;
- FLUSH(&sec);
- FLUSH(&nsec);
-}
-
-#pragma textflag NOSPLIT
-void
runtime·itoa(int32 n, byte *p, uint32 len)
{
byte *q, c;
diff --git a/src/pkg/runtime/os_solaris.c b/src/pkg/runtime/os_solaris.c
index c6c2a8a..e35d2b9 100644
--- a/src/pkg/runtime/os_solaris.c
+++ b/src/pkg/runtime/os_solaris.c
@@ -437,19 +437,6 @@
}
#pragma textflag NOSPLIT
-void
-time·now(int64 sec, int32 usec)
-{
- int64 ns;
-
- ns = runtime·nanotime();
- sec = ns / 1000000000LL;
- usec = ns - sec * 1000000000LL;
- FLUSH(&sec);
- FLUSH(&usec);
-}
-
-#pragma textflag NOSPLIT
int32
runtime·open(int8* path, int32 oflag, int32 mode)
{
diff --git a/src/pkg/runtime/os_windows.c b/src/pkg/runtime/os_windows.c
index d7f7a5a..a4d77f6 100644
--- a/src/pkg/runtime/os_windows.c
+++ b/src/pkg/runtime/os_windows.c
@@ -301,6 +301,13 @@
return 0;
}
+#pragma textflag NOSPLIT
+int64
+runtime·unixnano(void)
+{
+ return (runtime·systime(SYSTEM_TIME) - 116444736000000000LL) * 100LL;
+}
+
static void
badsystime(void)
{
@@ -314,22 +321,6 @@
return runtime·systime(INTERRUPT_TIME) * 100LL;
}
-#pragma textflag NOSPLIT
-void
-time·now(int64 sec, int32 usec)
-{
- int64 ns;
-
- // SystemTime is 100s of nanoseconds since January 1, 1601.
- // Convert to nanoseconds since January 1, 1970.
- ns = (runtime·systime(SYSTEM_TIME) - 116444736000000000LL) * 100LL;
-
- sec = ns / 1000000000LL;
- usec = ns - sec * 1000000000LL;
- FLUSH(&sec);
- FLUSH(&usec);
-}
-
// Calling stdcall on os stack.
#pragma textflag NOSPLIT
static void*
diff --git a/src/pkg/runtime/sys_darwin_amd64.s b/src/pkg/runtime/sys_darwin_amd64.s
index 2f98bfb..bd397d7 100644
--- a/src/pkg/runtime/sys_darwin_amd64.s
+++ b/src/pkg/runtime/sys_darwin_amd64.s
@@ -158,7 +158,7 @@
RET
// func now() (sec int64, nsec int32)
-TEXT time·now(SB),NOSPLIT,$8
+TEXT time·now(SB),NOSPLIT,$0-12
CALL nanotime<>(SB)
// generated code for
diff --git a/src/pkg/runtime/sys_plan9_386.s b/src/pkg/runtime/sys_plan9_386.s
index dfa0961..7432981 100644
--- a/src/pkg/runtime/sys_plan9_386.s
+++ b/src/pkg/runtime/sys_plan9_386.s
@@ -101,6 +101,19 @@
MOVL $-1, ret_hi+8(FP)
RET
+// func now() (sec int64, nsec int32)
+TEXT time·now(SB),NOSPLIT,$8-12
+ CALL runtime·nanotime(SB)
+ MOVL 0(SP), AX
+ MOVL 4(SP), DX
+
+ MOVL $1000000000, CX
+ DIVL CX
+ MOVL AX, sec+0(FP)
+ MOVL $0, sec+4(FP)
+ MOVL DX, nsec+8(FP)
+ RET
+
TEXT runtime·notify(SB),NOSPLIT,$0
MOVL $28, AX
INT $64
diff --git a/src/pkg/runtime/sys_plan9_amd64.s b/src/pkg/runtime/sys_plan9_amd64.s
index 08ddc3f..954c0c2 100644
--- a/src/pkg/runtime/sys_plan9_amd64.s
+++ b/src/pkg/runtime/sys_plan9_amd64.s
@@ -91,6 +91,26 @@
MOVQ AX, ret+8(FP)
RET
+// func now() (sec int64, nsec int32)
+TEXT time·now(SB),NOSPLIT,$8-12
+ CALL runtime·nanotime(SB)
+ MOVQ 0(SP), AX
+
+ // generated code for
+ // func f(x uint64) (uint64, uint64) { return x/1000000000, x%100000000 }
+ // adapted to reduce duplication
+ MOVQ AX, CX
+ MOVQ $1360296554856532783, AX
+ MULQ CX
+ ADDQ CX, DX
+ RCRQ $1, DX
+ SHRQ $29, DX
+ MOVQ DX, sec+0(FP)
+ IMULQ $1000000000, DX
+ SUBQ DX, CX
+ MOVL CX, nsec+8(FP)
+ RET
+
TEXT runtime·notify(SB),NOSPLIT,$0
MOVQ $28, BP
SYSCALL
diff --git a/src/pkg/runtime/sys_solaris_amd64.s b/src/pkg/runtime/sys_solaris_amd64.s
index 2055d6c..093315c 100644
--- a/src/pkg/runtime/sys_solaris_amd64.s
+++ b/src/pkg/runtime/sys_solaris_amd64.s
@@ -327,3 +327,23 @@
MOVQ libc·sched_yield(SB), AX
CALL AX
RET
+
+// func now() (sec int64, nsec int32)
+TEXT time·now(SB),NOSPLIT,$8-12
+ CALL runtime·nanotime(SB)
+ MOVQ 0(SP), AX
+
+ // generated code for
+ // func f(x uint64) (uint64, uint64) { return x/1000000000, x%100000000 }
+ // adapted to reduce duplication
+ MOVQ AX, CX
+ MOVQ $1360296554856532783, AX
+ MULQ CX
+ ADDQ CX, DX
+ RCRQ $1, DX
+ SHRQ $29, DX
+ MOVQ DX, sec+0(FP)
+ IMULQ $1000000000, DX
+ SUBQ DX, CX
+ MOVL CX, nsec+8(FP)
+ RET
diff --git a/src/pkg/runtime/sys_windows_386.s b/src/pkg/runtime/sys_windows_386.s
index f4d561f..a9e096f 100644
--- a/src/pkg/runtime/sys_windows_386.s
+++ b/src/pkg/runtime/sys_windows_386.s
@@ -365,3 +365,16 @@
CALL AX
MOVL BP, SP
RET
+
+// func now() (sec int64, nsec int32)
+TEXT time·now(SB),NOSPLIT,$8-12
+ CALL runtime·unixnano(SB)
+ MOVL 0(SP), AX
+ MOVL 4(SP), DX
+
+ MOVL $1000000000, CX
+ DIVL CX
+ MOVL AX, sec+0(FP)
+ MOVL $0, sec+4(FP)
+ MOVL DX, nsec+8(FP)
+ RET
diff --git a/src/pkg/runtime/sys_windows_amd64.s b/src/pkg/runtime/sys_windows_amd64.s
index e5890e0..21f73da 100644
--- a/src/pkg/runtime/sys_windows_amd64.s
+++ b/src/pkg/runtime/sys_windows_amd64.s
@@ -384,3 +384,24 @@
CALL AX
MOVQ 8(SP), SP
RET
+
+// func now() (sec int64, nsec int32)
+TEXT time·now(SB),NOSPLIT,$8-12
+ CALL runtime·unixnano(SB)
+ MOVQ 0(SP), AX
+
+ // generated code for
+ // func f(x uint64) (uint64, uint64) { return x/1000000000, x%100000000 }
+ // adapted to reduce duplication
+ MOVQ AX, CX
+ MOVQ $1360296554856532783, AX
+ MULQ CX
+ ADDQ CX, DX
+ RCRQ $1, DX
+ SHRQ $29, DX
+ MOVQ DX, sec+0(FP)
+ IMULQ $1000000000, DX
+ SUBQ DX, CX
+ MOVL CX, nsec+8(FP)
+ RET
+
