Subversion Repositories planix.SVN

#define CLREX           WORD    $0xf57ff01f
#define LDREX(a,r)      WORD    $(0xe<<28|0x01900f9f | (a)<<16 | (r)<<12)
/* `The order of operands is from left to right in dataflow order' - asm man */
#define STREX(v,a,r)    WORD    $(0xe<<28|0x01800f90 | (a)<<16 | (r)<<12 | (v)<<0)

/*
 * int cas(ulong *p, ulong ov, ulong nv);
 */

TEXT    cas+0(SB),0,$0          /* r0 holds p */
TEXT    casp+0(SB),0,$0         /* r0 holds p */
        MOVW    ov+4(FP), R1
        MOVW    nv+8(FP), R2
spincas:
        LDREX(0,3)      /*      LDREX   0(R0),R3        */
        CMP.S   R3, R1
        BNE     fail
        STREX(2,0,4)    /*      STREX   0(R0),R2,R4     */
        CMP.S   $0, R4
        BNE     spincas
        MOVW    $1, R0
        RET
fail:
        CLREX
        MOVW    $0, R0
        RET

TEXT _xinc(SB), $0      /* void _xinc(long *); */
TEXT ainc(SB), $0       /* long ainc(long *); */
spinainc:
        LDREX(0,3)      /*      LDREX   0(R0),R3        */
        ADD     $1,R3
        STREX(3,0,4)    /*      STREX   0(R0),R3,R4     */
        CMP.S   $0, R4
        BNE     spinainc
        MOVW    R3, R0
        RET

TEXT _xdec(SB), $0      /* long _xdec(long *); */
TEXT adec(SB), $0       /* long adec(long *); */
spinadec:
        LDREX(0,3)      /*      LDREX   0(R0),R3        */
        SUB     $1,R3
        STREX(3,0,4)    /*      STREX   0(R0),R3,R4     */
        CMP.S   $0, R4
        BNE     spinadec
        MOVW    R3, R0
        RET

TEXT loadlinked(SB), $0 /* long loadlinked(long *); */
        LDREX(0,0)      /*      LDREX   0(R0),R0        */
        RET

TEXT storecond(SB), $0  /* int storecond(long *, long); */
        MOVW    ov+4(FP), R3
        STREX(3,0,0)    /*      STREX   0(R0),R3,R0     */
        RSB     $1, R0
        RET