Subversion Repositories planix.SVN

/*
 * return from user-mode exception.
 * expects new SPSR in R0.  R13 must point to ureg->type.
 */
_rfue:
TEXT rfue(SB), 1, $-4
//      CPSID
//      BIC     $PsrMbz, R0             /* force little-endian upon return */
        MOVW    R0, SPSR                /* ... */

        /*
         * order on stack is type, psr, pc, but RFEV7 needs pc, psr.
         * step on type and previous word to hold temporary values.
         * we could instead change the order in which psr & pc are pushed.
         */
        MOVW    4(R13), R1              /* psr */
        MOVW    8(R13), R2              /* pc */
        MOVW    R2, 4(R13)              /* pc */
        MOVW    R1, 8(R13)              /* psr */

        MOVM.DB.S (R13), [R0-R14]       /* restore user registers */
        ADD     $4, R13                 /* pop type, sp -> pc */

#ifdef OLDWAY
        ADD     $(2*4), R13             /* pop past ureg->{type+psr} to pc */
        /*
         * this used to work on arm arch v[567] and still works on cpu 0.
         * for some reason it sometimes sets PsrBigend on cpu 1.
         * Ureg's tail was:
         *
         * typedef struct Ureg {
         *      ⋯
         *      ulong   type;   /* of exception */
         *      ulong   psr;
         *      ulong   pc;     /* interrupted addr */
         * } Ureg;
         */
        RFE                             /* MOVM.IA.S.W (R13), [R15] */
#endif
//      SETEND(0)
        RFEV7W(13)