loadandclearword_hpux_parisc_acc.s

Pegasus is an open-source implementationof the DMTF CIM and WBEM standards. It is designed to be por

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;
; LoadAndClearWord_HPUX_PARISC_ACC.s:
; HP-UX PA-RISC assembly language routine for spinlock support.
;

    .code
#ifdef __LP64__
    .level 2.0W
#else
    .level 1.1
#endif
    .export LoadAndClearWord,entry,priv_lev=3,rtnval=gr
    .proc

LoadAndClearWord
    .callinfo no_calls
    .enter

; create a 16 byte aligned pointer to the load+clear word area
    addi        15,%arg0,%arg2  ; add 15 to the pointer to round up

#ifdef __LP64__
    depdi       0,63,4,%arg2    ; mask the lower 4 bits (64-bit)
#else
    depi        0,31,4,%arg2    ; mask the lower 4 bits (32-bit)
#endif

#ifdef __LP64__
    bve       (%r2)          ; return 0 if already locked, else !0
#else
    bv        (%r2)          ; return 0 if already locked, else !0
#endif
    ldcws,co  (%arg2),%ret0  ; (in branch delay slot)
                        ; load and clear (coherent) the spinlock word

; This code is never executed.  This endless loop reduces the
; prefetching after mispredicted bv on pre PA 8700 processors.
; Leave this dead code here to improve performance.

load_and_clear_loop
      b load_and_clear_loop
      nop
     .leave
     .procend