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/*
 *  systrap.S
 *
 *  This file contains emulated system calls using software trap 0.
 *  The following calls are supported:
 *
 *    + SYS_exit        (halt)
 *    + SYS_irqdis      (disable interrupts)
 *    + SYS_irqset      (set interrupt level)
 * 
 *  COPYRIGHT:
 *
 *  COPYRIGHT (c) 1995. European Space Agency.
 *
 *  This terms of the RTEMS license apply to this file.
 *
 */

#include <asm.h>
#include "syscall.h"

        .seg    "text"
        /*
         *  system call
         *
         *  On entry:
         *
         *    l0 = psr (from trap table)
         *    l1 = pc
         *    l2 = npc
         *    g1 = system call id
         */

        PUBLIC(syscall)

SYM(syscall):

        subcc   %g1, 2, %g0             ! syscall 2, disable interrupts
        bne     3f
        or      %l0, 0x0f00, %l4        ! set PIL=15
        mov     %l4, %psr
        or      %l0, SPARC_PSR_ET_MASK, %i0     ! return old psr with ET=1
        ba,a    9f
3:
        subcc   %g1, 3, %g0             ! syscall 3, enable interrupts
        bne     1f
        and     %i0, SPARC_PSR_PIL_MASK, %l4
        andn    %l0, SPARC_PSR_PIL_MASK, %l5
        or      %l5, %l4, %l4
        mov     %l4, %psr
        ba,a    9f

1:                                      
        ta      0                        ! halt 
9:                                      ! leave
        mov     0, %g1                  ! clear %g1 
        jmpl    %l2, %g0
        rett    %l2 + 4

        PUBLIC(sparc_disable_interrupts)

SYM(sparc_disable_interrupts):

        mov     SYS_irqdis, %g1
        ta      0
        retl
        nop

        PUBLIC(sparc_enable_interrupts)

SYM(sparc_enable_interrupts):

        mov     SYS_irqen, %g1
        ta      0
        retl
        nop

/* end of file */