/***************************************************************************
 *
 * i86/atomic.s
 *
 * $Id$
 *
 ***************************************************************************
 *
 * Copyright 2005-2006 The Apache Software Foundation or its licensors,
 * as applicable.
 *
 * Copyright 2003-2006 Rogue Wave Software.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 * 
 **************************************************************************/

    .text
    .align 4

/***************************************************************************
 * extern "C" char __rw_atomic_xchg8 (char *x, char y);
 *
 * Atomically assigns the 8-bit value y to *x and returns
 * the original (before assignment) 8-bit value of *x.
 **************************************************************************/

    .globl __rw_atomic_xchg8
__rw_atomic_xchg8:                 /* ; char (char *x, char y)        */
    mov           4(%esp), %ecx    /* ; %ecx = x                      */
    movb          8(%esp), %al     /* ; %al = y                       */
    xchg          %al, (%ecx)      /* ; %al <-> (%ecx)                */
    ret


/***************************************************************************
 * extern "C" short __rw_atomic_xchg16 (short *x, short y);
 *
 * Atomically assigns the 16-bit value y to *x and returns
 * the original (before assignment) 16-bit value of *x.
 **************************************************************************/

    .globl __rw_atomic_xchg16
__rw_atomic_xchg16:                /* ; short (short *x, short y)     */
    mov           4(%esp), %ecx    /* ; %ecx = x                      */
    mov           8(%esp), %eax    /* ; %eax = y                      */
    xchgw         %ax, (%ecx)      /* ; %ax <-> (%ecx)                */
    ret


/***************************************************************************
 * extern "C" int __rw_atomic_xchg32 (int *x, int y);
 *
 * Atomically assigns the 32-bit value y to *x and returns
 * the original (before assignment) 32-bit value of *x.
 **************************************************************************/

    .globl __rw_atomic_xchg32
__rw_atomic_xchg32:                /* ; int (int *x, int y)           */
    movl          4(%esp), %ecx    /* ; %ecx = x                      */
    movl          8(%esp), %eax    /* ; %eax = y                      */
    xchgl         %eax, (%ecx)     /* ; %eax <-> (%ecx)               */
    ret


/***************************************************************************
 * extern "C" char __rw_atomic_add8 (char *x, int y);
 *
 * Atomically increments the 8-bit value *x by y and returns
 * the new (after increment) 8-bit value of *x.
 **************************************************************************/

    .globl __rw_atomic_add8
__rw_atomic_add8:                  /* ; char (char *dst, int inc)     */
    mov            4(%esp), %ecx   /* ; %ecx = dst                    */
    mov            8(%esp), %eax   /* ; %eax = inc                    */
    mov            %eax, %edx      /* ; */

    lock
    xaddb          %al, (%ecx)     /* ; tmp = *dst;
                                      ; dst += inc;
                                      ; %al = tmp                     */

    add            %edx, %eax      /* ; return %eax + inc             */
    ret


/***************************************************************************
 * extern "C" short __rw_atomic_add16 (short *x, short y);
 *
 * Atomically increments the 16-bit value *x by y and returns
 * the new (after increment) 16-bit value of *x.
 **************************************************************************/

     .globl __rw_atomic_add16
__rw_atomic_add16:                 /* ; long (long *dst, long inc)    */
    mov            4(%esp), %ecx   /* ; %ecx = dst                    */
    mov            8(%esp), %eax   /* ; %eax = inc                    */
    mov            %eax, %edx      /* ; */

    lock
    xaddw          %ax, (%ecx)     /* ; tmp = *dst;
                                      ; dst += inc;
                                      ; eax = tmp                     */

    add            %edx, %eax      /* ; return %eax + inc             */
    ret


/***************************************************************************
 * extern "C" int __rw_atomic_add32 (int *x, int y);
 *
 * Atomically increments the 32-bit value *x by y and returns
 * the new (after increment) 32-bit value of *x.
 **************************************************************************/

    .globl __rw_atomic_add32
__rw_atomic_add32:                 /* ; long (long *dst, long inc)    */
    movl           4(%esp), %ecx   /* ; %ecx = dst                    */
    movl           8(%esp), %edx   /* ; %edx = inc                    */
    movl           %edx, %eax      /* ; */

    lock
    xaddl          %eax, (%ecx)    /* ; tmp = *dst;
                                      ; dst += inc;
                                      ; %eax = tmp                    */

    addl           %edx, %eax      /* ; return %eax + inc             */
    ret