Re: PATCH: Fix ll/sc for mips (take 3)

["H . J . Lu" <hjl@lucon.org>]

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"?


H.J.
---
2002-02-04  H.J. Lu  <hjl@gnu.org>

	* sysdeps/mips/pspinlock.c (__pthread_spin_lock): Not use
	branch likely.
	* sysdeps/mips/pt-machine.h (testandset): Liekwise.
	(__compare_and_swap): Liekwise.

2002-02-04  H.J. Lu  <hjl@gnu.org>

	* sysdeps/mips/atomicity.h (exchange_and_add): Not use branch
	likely.
	(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	Mon Feb  4 17:09:02 2002
@@ -40,7 +40,7 @@ __pthread_spin_lock (pthread_spinlock_t 
      "bnez	%1,1b\n\t"
      " li	%2,1\n\t"
      "sc	%2,%0\n\t"
-     "beqzl	%2,1b\n\t"
+     "beqz	%2,1b\n\t"
      " ll	%1,%3\n\t"
      ".set	pop"
      : "=m" (*lock), "=&r" (tmp1), "=&r" (tmp2)
--- libc/linuxthreads/sysdeps/mips/pt-machine.h.llsc	Mon Feb  4 13:45:01 2002
+++ libc/linuxthreads/sysdeps/mips/pt-machine.h	Mon Feb  4 17:09:36 2002
@@ -66,7 +66,7 @@ __compare_and_swap (long int *p, long in
      " move	%0,$0\n\t"
      "move	%0,%4\n\t"
      "sc	%0,%2\n\t"
-     "beqzl	%0,1b\n\t"
+     "beqz	%0,1b\n\t"
      " ll	%1,%5\n\t"
      ".set	pop\n"
      "2:\n\t"
--- libc/sysdeps/mips/atomicity.h.llsc	Mon Feb  4 13:45:18 2002
+++ libc/sysdeps/mips/atomicity.h	Mon Feb  4 17:14:48 2002
@@ -32,15 +32,15 @@ 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"
+     "beqz	%1,1b\n\t"
+     " nop\n\t"
      ".set	pop\n\t"
      "/* End exchange & add */"
      : "=&r"(result), "=&r"(tmp), "=m"(*mem)
@@ -57,15 +57,15 @@ 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"
+     "beqz	%0,1b\n\t"
+     " nop\n\t"
      ".set	pop\n\t"
      "/* End atomic add */"
      : "=&r"(result), "=m"(*mem)
@@ -89,7 +89,7 @@ compare_and_swap (volatile long int *p, 
      " move	%0,$0\n\t"
      "move	%0,%4\n\t"
      "sc	%0,%2\n\t"
-     "beqzl	%0,1b\n\t"
+     "beqz	%0,1b\n\t"
      " ll	%1,%5\n\t"
      ".set	pop\n"
      "2:\n\t"
--- 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	Mon Feb  4 17:19:06 2002
@@ -42,16 +42,16 @@ _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"
+     "ll	%0,%3\n"
      ".set	push\n\t"
      ".set	noreorder\n\t"
      "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"
+     "beqz	%1,1b\n\t"
+     " nop\n\t"
      ".set	pop\n"
      "2:\n\t"
      "/* End test and set */"