On Mon, Feb 04, 2002 at 09:58:04PM -0500, Daniel Jacobowitz wrote:
> On Mon, Feb 04, 2002 at 05:28:57PM -0800, H . J . Lu wrote:
> > On Mon, Feb 04, 2002 at 04:46:07PM +0000, Dominic Sweetman wrote:
> > >
> > > H . J . Lu (hjl@lucon.org) writes:
> > >
> > > > I can change glibc not to use branch-likely without using nop. But it
> > > > may require one or two instructions outside of the loop. Should I do
> > > > it given what we know now?
> > >
> > > I would not recommend using "branch likely" in assembler coding, if
> > > that's what you're asking.
> > >
> >
> > Here is a patch to remove branch likely. But I couldn't find a way
> > not to fill the delay slot with nop. BTW, is that safe to remove
> > ".set noreorder"?
>
> You mean, if there is nothing which can be put there? Yes, it's safe.
>
Here is a new patch. I removed the extra "ll" in the delay slot.
H.J.
---
2002-02-05 H.J. Lu <hjl@gnu.org>
* sysdeps/mips/pspinlock.c (__pthread_spin_lock): Not use
branch likely. Remove ".set noreorder".
* sysdeps/mips/pt-machine.h (testandset): Liekwise.
(__compare_and_swap): Liekwise.
2002-02-05 H.J. Lu <hjl@gnu.org>
* sysdeps/mips/atomicity.h (exchange_and_add): Not use branch
likely. Remove ".set noreorder".
(atomic_add): Likewise.
(compare_and_swap): Likewise.
* sysdeps/unix/sysv/linux/mips/sys/tas.h (_test_and_set):
Likewise.
--- libc/linuxthreads/sysdeps/mips/pspinlock.c.llsc Mon Feb 4 13:45:01 2002
+++ libc/linuxthreads/sysdeps/mips/pspinlock.c Tue Feb 5 11:26:22 2002
@@ -32,17 +32,13 @@ __pthread_spin_lock (pthread_spinlock_t
unsigned int tmp1, tmp2;
asm volatile
- ("\t\t\t# spin_lock\n\t"
- "ll %1,%3\n"
+ ("\t\t\t# spin_lock\n"
"1:\n\t"
- ".set push\n\t"
- ".set noreorder\n\t"
+ "ll %1,%3\n"
"bnez %1,1b\n\t"
" li %2,1\n\t"
"sc %2,%0\n\t"
- "beqzl %2,1b\n\t"
- " ll %1,%3\n\t"
- ".set pop"
+ "beqz %2,1b\n\t"
: "=m" (*lock), "=&r" (tmp1), "=&r" (tmp2)
: "m" (*lock)
: "memory");
--- libc/linuxthreads/sysdeps/mips/pt-machine.h.llsc Mon Feb 4 13:45:01 2002
+++ libc/linuxthreads/sysdeps/mips/pt-machine.h Tue Feb 5 11:26:51 2002
@@ -57,18 +57,14 @@ __compare_and_swap (long int *p, long in
long int ret, temp;
__asm__ __volatile__
- ("/* Inline compare & swap */\n\t"
- "ll %1,%5\n"
+ ("/* Inline compare & swap */\n"
"1:\n\t"
- ".set push\n\t"
- ".set noreorder\n\t"
+ "ll %1,%5\n"
"bne %1,%3,2f\n\t"
" move %0,$0\n\t"
"move %0,%4\n\t"
"sc %0,%2\n\t"
- "beqzl %0,1b\n\t"
- " ll %1,%5\n\t"
- ".set pop\n"
+ "beqz %0,1b\n\t"
"2:\n\t"
"/* End compare & swap */"
: "=&r" (ret), "=&r" (temp), "=m" (*p)
--- libc/sysdeps/mips/atomicity.h.llsc Mon Feb 4 13:45:18 2002
+++ libc/sysdeps/mips/atomicity.h Tue Feb 5 11:25:09 2002
@@ -32,16 +32,12 @@ exchange_and_add (volatile uint32_t *mem
int result, tmp;
__asm__ __volatile__
- ("/* Inline exchange & add */\n\t"
+ ("/* Inline exchange & add */\n"
+ "1:\n"
"ll %0,%3\n"
- "1:\n\t"
"addu %1,%4,%0\n\t"
"sc %1,%2\n\t"
- ".set push\n\t"
- ".set noreorder\n\t"
- "beqzl %1,1b\n\t"
- " ll %0,%3\n\t"
- ".set pop\n\t"
+ "beqz %1,1b\n\t"
"/* End exchange & add */"
: "=&r"(result), "=&r"(tmp), "=m"(*mem)
: "m" (*mem), "r"(val)
@@ -57,16 +53,12 @@ atomic_add (volatile uint32_t *mem, int
int result;
__asm__ __volatile__
- ("/* Inline atomic add */\n\t"
- "ll %0,%2\n"
+ ("/* Inline atomic add */\n"
"1:\n\t"
+ "ll %0,%2\n"
"addu %0,%3,%0\n\t"
"sc %0,%1\n\t"
- ".set push\n\t"
- ".set noreorder\n\t"
- "beqzl %0,1b\n\t"
- " ll %0,%2\n\t"
- ".set pop\n\t"
+ "beqz %0,1b\n\t"
"/* End atomic add */"
: "=&r"(result), "=m"(*mem)
: "m" (*mem), "r"(val)
@@ -80,18 +72,14 @@ compare_and_swap (volatile long int *p,
long int ret, temp;
__asm__ __volatile__
- ("/* Inline compare & swap */\n\t"
- "ll %1,%5\n"
+ ("/* Inline compare & swap */\n"
"1:\n\t"
- ".set push\n\t"
- ".set noreorder\n\t"
+ "ll %1,%5\n"
"bne %1,%3,2f\n\t"
" move %0,$0\n\t"
"move %0,%4\n\t"
"sc %0,%2\n\t"
- "beqzl %0,1b\n\t"
- " ll %1,%5\n\t"
- ".set pop\n"
+ "beqz %0,1b\n\t"
"2:\n\t"
"/* End compare & swap */"
: "=&r" (ret), "=&r" (temp), "=m" (*p)
--- libc/sysdeps/unix/sysv/linux/mips/sys/tas.h.llsc Mon Feb 4 13:45:28 2002
+++ libc/sysdeps/unix/sysv/linux/mips/sys/tas.h Tue Feb 5 11:25:34 2002
@@ -42,17 +42,13 @@ _test_and_set (int *p, int v) __THROW
int r, t;
__asm__ __volatile__
- ("/* Inline test and set */\n\t"
- "ll %0,%3\n"
+ ("/* Inline test and set */\n"
"1:\n\t"
- ".set push\n\t"
- ".set noreorder\n\t"
+ "ll %0,%3\n"
"beq %0,%4,2f\n\t"
" move %1,%4\n\t"
"sc %1,%2\n\t"
- "beqzl %1,1b\n\t"
- " ll %0,%3\n\t"
- ".set pop\n"
+ "beqz %1,1b\n\t"
"2:\n\t"
"/* End test and set */"
: "=&r" (r), "=&r" (t), "=m" (*p)
