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Diffstat (limited to 'nsprpub/pr/src/md/unix/os_SunOS_ultrasparc.s')
| -rw-r--r-- | nsprpub/pr/src/md/unix/os_SunOS_ultrasparc.s | 173 |
1 files changed, 173 insertions, 0 deletions
diff --git a/nsprpub/pr/src/md/unix/os_SunOS_ultrasparc.s b/nsprpub/pr/src/md/unix/os_SunOS_ultrasparc.s new file mode 100644 index 0000000000..32bf7884ac --- /dev/null +++ b/nsprpub/pr/src/md/unix/os_SunOS_ultrasparc.s @@ -0,0 +1,173 @@ +! -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- +! +! This Source Code Form is subject to the terms of the Mozilla Public +! License, v. 2.0. If a copy of the MPL was not distributed with this +! file, You can obtain one at http://mozilla.org/MPL/2.0/. + +! +! atomic increment, decrement and swap routines for V8+ sparc (ultrasparc) +! using CAS (compare-and-swap) atomic instructions +! +! this MUST be compiled with an ultrasparc-aware assembler +! +! standard asm linkage macros; this module must be compiled +! with the -P option (use C preprocessor) + +#include <sys/asm_linkage.h> + +! ====================================================================== +! +! Perform the sequence a = a + 1 atomically with respect to other +! fetch-and-adds to location a in a wait-free fashion. +! +! usage : val = PR_AtomicIncrement(address) +! return: current value (you'd think this would be old val) +! +! ----------------------- +! Note on REGISTER USAGE: +! as this is a LEAF procedure, a new stack frame is not created; +! we use the caller's stack frame so what would normally be %i (input) +! registers are actually %o (output registers). Also, we must not +! overwrite the contents of %l (local) registers as they are not +! assumed to be volatile during calls. +! +! So, the registers used are: +! %o0 [input] - the address of the value to increment +! %o1 [local] - work register +! %o2 [local] - work register +! %o3 [local] - work register +! ----------------------- + + ENTRY(PR_AtomicIncrement) ! standard assembler/ELF prologue + +retryAI: + ld [%o0], %o2 ! set o2 to the current value + add %o2, 0x1, %o3 ! calc the new value + mov %o3, %o1 ! save the return value + cas [%o0], %o2, %o3 ! atomically set if o0 hasn't changed + cmp %o2, %o3 ! see if we set the value + bne retryAI ! if not, try again + nop ! empty out the branch pipeline + retl ! return back to the caller + mov %o1, %o0 ! set the return code to the new value + + SET_SIZE(PR_AtomicIncrement) ! standard assembler/ELF epilogue + +! +! end +! +! ====================================================================== +! + +! ====================================================================== +! +! Perform the sequence a = a - 1 atomically with respect to other +! fetch-and-decs to location a in a wait-free fashion. +! +! usage : val = PR_AtomicDecrement(address) +! return: current value (you'd think this would be old val) +! +! ----------------------- +! Note on REGISTER USAGE: +! as this is a LEAF procedure, a new stack frame is not created; +! we use the caller's stack frame so what would normally be %i (input) +! registers are actually %o (output registers). Also, we must not +! overwrite the contents of %l (local) registers as they are not +! assumed to be volatile during calls. +! +! So, the registers used are: +! %o0 [input] - the address of the value to increment +! %o1 [local] - work register +! %o2 [local] - work register +! %o3 [local] - work register +! ----------------------- + + ENTRY(PR_AtomicDecrement) ! standard assembler/ELF prologue + +retryAD: + ld [%o0], %o2 ! set o2 to the current value + sub %o2, 0x1, %o3 ! calc the new value + mov %o3, %o1 ! save the return value + cas [%o0], %o2, %o3 ! atomically set if o0 hasn't changed + cmp %o2, %o3 ! see if we set the value + bne retryAD ! if not, try again + nop ! empty out the branch pipeline + retl ! return back to the caller + mov %o1, %o0 ! set the return code to the new value + + SET_SIZE(PR_AtomicDecrement) ! standard assembler/ELF epilogue + +! +! end +! +! ====================================================================== +! + +! ====================================================================== +! +! Perform the sequence a = b atomically with respect to other +! fetch-and-stores to location a in a wait-free fashion. +! +! usage : old_val = PR_AtomicSet(address, newval) +! +! ----------------------- +! Note on REGISTER USAGE: +! as this is a LEAF procedure, a new stack frame is not created; +! we use the caller's stack frame so what would normally be %i (input) +! registers are actually %o (output registers). Also, we must not +! overwrite the contents of %l (local) registers as they are not +! assumed to be volatile during calls. +! +! So, the registers used are: +! %o0 [input] - the address of the value to increment +! %o1 [input] - the new value to set for [%o0] +! %o2 [local] - work register +! %o3 [local] - work register +! ----------------------- + + ENTRY(PR_AtomicSet) ! standard assembler/ELF prologue + +retryAS: + ld [%o0], %o2 ! set o2 to the current value + mov %o1, %o3 ! set up the new value + cas [%o0], %o2, %o3 ! atomically set if o0 hasn't changed + cmp %o2, %o3 ! see if we set the value + bne retryAS ! if not, try again + nop ! empty out the branch pipeline + retl ! return back to the caller + mov %o3, %o0 ! set the return code to the prev value + + SET_SIZE(PR_AtomicSet) ! standard assembler/ELF epilogue + +! +! end +! +! ====================================================================== +! + +! ====================================================================== +! +! Perform the sequence a = a + b atomically with respect to other +! fetch-and-adds to location a in a wait-free fashion. +! +! usage : newval = PR_AtomicAdd(address, val) +! return: the value after addition +! + ENTRY(PR_AtomicAdd) ! standard assembler/ELF prologue + +retryAA: + ld [%o0], %o2 ! set o2 to the current value + add %o2, %o1, %o3 ! calc the new value + mov %o3, %o4 ! save the return value + cas [%o0], %o2, %o3 ! atomically set if o0 hasn't changed + cmp %o2, %o3 ! see if we set the value + bne retryAA ! if not, try again + nop ! empty out the branch pipeline + retl ! return back to the caller + mov %o4, %o0 ! set the return code to the new value + + SET_SIZE(PR_AtomicAdd) ! standard assembler/ELF epilogue + +! +! end +! |