| |
| /* |
| * Copyright (C) Igor Sysoev |
| * Copyright (C) Nginx, Inc. |
| */ |
| |
| |
| /* |
| * The ppc assembler treats ";" as comment, so we have to use "\n". |
| * The minus in "bne-" is a hint for the branch prediction unit that |
| * this branch is unlikely to be taken. |
| * The "1b" means the nearest backward label "1" and the "1f" means |
| * the nearest forward label "1". |
| * |
| * The "b" means that the base registers can be used only, i.e. |
| * any register except r0. The r0 register always has a zero value and |
| * could not be used in "addi r0, r0, 1". |
| * The "=&b" means that no input registers can be used. |
| * |
| * "sync" read and write barriers |
| * "isync" read barrier, is faster than "sync" |
| * "eieio" write barrier, is faster than "sync" |
| * "lwsync" write barrier, is faster than "eieio" on ppc64 |
| */ |
| |
| #if (NGX_PTR_SIZE == 8) |
| |
| static ngx_inline ngx_atomic_uint_t |
| ngx_atomic_cmp_set(ngx_atomic_t *lock, ngx_atomic_uint_t old, |
| ngx_atomic_uint_t set) |
| { |
| ngx_atomic_uint_t res, temp; |
| |
| __asm__ volatile ( |
| |
| " li %0, 0 \n" /* preset "0" to "res" */ |
| " lwsync \n" /* write barrier */ |
| "1: \n" |
| " ldarx %1, 0, %2 \n" /* load from [lock] into "temp" */ |
| /* and store reservation */ |
| " cmpd %1, %3 \n" /* compare "temp" and "old" */ |
| " bne- 2f \n" /* not equal */ |
| " stdcx. %4, 0, %2 \n" /* store "set" into [lock] if reservation */ |
| /* is not cleared */ |
| " bne- 1b \n" /* the reservation was cleared */ |
| " isync \n" /* read barrier */ |
| " li %0, 1 \n" /* set "1" to "res" */ |
| "2: \n" |
| |
| : "=&b" (res), "=&b" (temp) |
| : "b" (lock), "b" (old), "b" (set) |
| : "cc", "memory"); |
| |
| return res; |
| } |
| |
| |
| static ngx_inline ngx_atomic_int_t |
| ngx_atomic_fetch_add(ngx_atomic_t *value, ngx_atomic_int_t add) |
| { |
| ngx_atomic_uint_t res, temp; |
| |
| __asm__ volatile ( |
| |
| " lwsync \n" /* write barrier */ |
| "1: ldarx %0, 0, %2 \n" /* load from [value] into "res" */ |
| /* and store reservation */ |
| " add %1, %0, %3 \n" /* "res" + "add" store in "temp" */ |
| " stdcx. %1, 0, %2 \n" /* store "temp" into [value] if reservation */ |
| /* is not cleared */ |
| " bne- 1b \n" /* try again if reservation was cleared */ |
| " isync \n" /* read barrier */ |
| |
| : "=&b" (res), "=&b" (temp) |
| : "b" (value), "b" (add) |
| : "cc", "memory"); |
| |
| return res; |
| } |
| |
| |
| #if (NGX_SMP) |
| #define ngx_memory_barrier() \ |
| __asm__ volatile ("isync \n lwsync \n" ::: "memory") |
| #else |
| #define ngx_memory_barrier() __asm__ volatile ("" ::: "memory") |
| #endif |
| |
| #else |
| |
| static ngx_inline ngx_atomic_uint_t |
| ngx_atomic_cmp_set(ngx_atomic_t *lock, ngx_atomic_uint_t old, |
| ngx_atomic_uint_t set) |
| { |
| ngx_atomic_uint_t res, temp; |
| |
| __asm__ volatile ( |
| |
| " li %0, 0 \n" /* preset "0" to "res" */ |
| " eieio \n" /* write barrier */ |
| "1: \n" |
| " lwarx %1, 0, %2 \n" /* load from [lock] into "temp" */ |
| /* and store reservation */ |
| " cmpw %1, %3 \n" /* compare "temp" and "old" */ |
| " bne- 2f \n" /* not equal */ |
| " stwcx. %4, 0, %2 \n" /* store "set" into [lock] if reservation */ |
| /* is not cleared */ |
| " bne- 1b \n" /* the reservation was cleared */ |
| " isync \n" /* read barrier */ |
| " li %0, 1 \n" /* set "1" to "res" */ |
| "2: \n" |
| |
| : "=&b" (res), "=&b" (temp) |
| : "b" (lock), "b" (old), "b" (set) |
| : "cc", "memory"); |
| |
| return res; |
| } |
| |
| |
| static ngx_inline ngx_atomic_int_t |
| ngx_atomic_fetch_add(ngx_atomic_t *value, ngx_atomic_int_t add) |
| { |
| ngx_atomic_uint_t res, temp; |
| |
| __asm__ volatile ( |
| |
| " eieio \n" /* write barrier */ |
| "1: lwarx %0, 0, %2 \n" /* load from [value] into "res" */ |
| /* and store reservation */ |
| " add %1, %0, %3 \n" /* "res" + "add" store in "temp" */ |
| " stwcx. %1, 0, %2 \n" /* store "temp" into [value] if reservation */ |
| /* is not cleared */ |
| " bne- 1b \n" /* try again if reservation was cleared */ |
| " isync \n" /* read barrier */ |
| |
| : "=&b" (res), "=&b" (temp) |
| : "b" (value), "b" (add) |
| : "cc", "memory"); |
| |
| return res; |
| } |
| |
| |
| #if (NGX_SMP) |
| #define ngx_memory_barrier() \ |
| __asm__ volatile ("isync \n eieio \n" ::: "memory") |
| #else |
| #define ngx_memory_barrier() __asm__ volatile ("" ::: "memory") |
| #endif |
| |
| #endif |
| |
| |
| #define ngx_cpu_pause() |
