source: mainline/kernel/arch/ia64/src/context.S@ df4ed85

#
# Copyright (c) 2005 Jakub Jermar
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.text

.global context_save_arch
.global context_restore_arch

context_save_arch:
        alloc loc0 = ar.pfs, 1, 8, 0, 0
        mov loc1 = ar.unat      ;;
        /* loc2 */
        mov loc3 = ar.rsc

        .auto

        /*
         * Flush dirty registers to backing store.
         * After this ar.bsp and ar.bspstore are equal.
         */
        flushrs
        mov loc4 = ar.bsp       
        
        /*
         * Put RSE to enforced lazy mode.
         * So that ar.rnat can be read.
         */
        and loc5 = ~3, loc3
        mov ar.rsc = loc5
        mov loc5 = ar.rnat

        .explicit

        mov loc6 = ar.lc
        
        /*
         * Save application registers
         */
        st8 [in0] = loc0, 8     ;;      /* save ar.pfs */
        st8 [in0] = loc1, 8     ;;      /* save ar.unat (caller) */
        mov loc2 = in0          ;;
        add in0 = 8, in0        ;;      /* skip ar.unat (callee) */
        st8 [in0] = loc3, 8     ;;      /* save ar.rsc */
        st8 [in0] = loc4, 8     ;;      /* save ar.bsp */
        st8 [in0] = loc5, 8     ;;      /* save ar.rnat */
        st8 [in0] = loc6, 8     ;;      /* save ar.lc */
        
        /*
         * Save general registers including NaT bits
         */
        st8.spill [in0] = r1, 8         ;;
        st8.spill [in0] = r4, 8         ;;
        st8.spill [in0] = r5, 8         ;;
        st8.spill [in0] = r6, 8         ;;
        st8.spill [in0] = r7, 8         ;;
        st8.spill [in0] = r12, 8        ;;      /* save sp */
        st8.spill [in0] = r13, 8        ;;

        mov loc3 = ar.unat              ;;
        st8 [loc2] = loc3               /* save ar.unat (callee) */

        /*
         * Save branch registers
         */
        mov loc2 = b0           ;;
        st8 [in0] = loc2, 8             /* save pc */
        mov loc3 = b1           ;;
        st8 [in0] = loc3, 8
        mov loc4 = b2           ;;
        st8 [in0] = loc4, 8
        mov loc5 = b3           ;;
        st8 [in0] = loc5, 8
        mov loc6 = b4           ;;
        st8 [in0] = loc6, 8
        mov loc7 = b5           ;;
        st8 [in0] = loc7, 8

        /*
         * Save predicate registers
         */
        mov loc2 = pr           ;;
        st8 [in0] = loc2, 16;;          /* Next fpu registers should be spilled to 16B aligned address */

        /*
         * Save floating-point registers.
         */
        stf.spill [in0] = f2, 16 ;;
        stf.spill [in0] = f3, 16 ;;
        stf.spill [in0] = f4, 16 ;;
        stf.spill [in0] = f5, 16 ;;

        stf.spill [in0] = f16, 16 ;;
        stf.spill [in0] = f17, 16 ;;
        stf.spill [in0] = f18, 16 ;;
        stf.spill [in0] = f19, 16 ;;
        stf.spill [in0] = f20, 16 ;;
        stf.spill [in0] = f21, 16 ;;
        stf.spill [in0] = f22, 16 ;;
        stf.spill [in0] = f23, 16 ;;
        stf.spill [in0] = f24, 16 ;;
        stf.spill [in0] = f25, 16 ;;
        stf.spill [in0] = f26, 16 ;;
        stf.spill [in0] = f27, 16 ;;
        stf.spill [in0] = f28, 16 ;;
        stf.spill [in0] = f29, 16 ;;
        stf.spill [in0] = f30, 16 ;;
        stf.spill [in0] = f31, 16 ;;

        mov ar.unat = loc1
        
        add r8 = r0, r0, 1              /* context_save returns 1 */
        br.ret.sptk.many b0

context_restore_arch:
        alloc loc0 = ar.pfs, 1, 9, 0, 0 ;;

        ld8 loc0 = [in0], 8     ;;      /* load ar.pfs */
        ld8 loc1 = [in0], 8     ;;      /* load ar.unat (caller) */
        ld8 loc2 = [in0], 8     ;;      /* load ar.unat (callee) */
        ld8 loc3 = [in0], 8     ;;      /* load ar.rsc */
        ld8 loc4 = [in0], 8     ;;      /* load ar.bsp */
        ld8 loc5 = [in0], 8     ;;      /* load ar.rnat */
        ld8 loc6 = [in0], 8     ;;      /* load ar.lc */
        
        .auto   

        /*
         * Invalidate the ALAT
         */
        invala

        /*
         * Put RSE to enforced lazy mode.
         * So that ar.bspstore and ar.rnat can be written.
         */
        movl loc8 = ~3
        and loc8 = loc3, loc8
        mov ar.rsc = loc8

        /*
         * Flush dirty registers to backing store.
         * We do this because we want the following move
         * to ar.bspstore to assign the same value to ar.bsp.
         */
        flushrs

        /*
         * Restore application registers
         */
        mov ar.bspstore = loc4  /* rse.bspload = ar.bsp = ar.bspstore = loc4 */
        mov ar.rnat = loc5
        mov ar.pfs = loc0
        mov ar.rsc = loc3

        .explicit

        mov ar.unat = loc2      ;;
        mov ar.lc = loc6
        
        /*
         * Restore general registers including NaT bits
         */
        ld8.fill r1 = [in0], 8  ;;
        ld8.fill r4 = [in0], 8  ;;
        ld8.fill r5 = [in0], 8  ;;
        ld8.fill r6 = [in0], 8  ;;
        ld8.fill r7 = [in0], 8  ;;
        ld8.fill r12 = [in0], 8 ;;      /* restore sp */
        ld8.fill r13 = [in0], 8 ;;

        /* 
         * Restore branch registers
         */
        ld8 loc2 = [in0], 8     ;;      /* restore pc */
        mov b0 = loc2
        ld8 loc3 = [in0], 8     ;;
        mov b1 = loc3
        ld8 loc4 = [in0], 8     ;;
        mov b2 = loc4
        ld8 loc5 = [in0], 8     ;;
        mov b3 = loc5
        ld8 loc6 = [in0], 8     ;;
        mov b4 = loc6
        ld8 loc7 = [in0], 8     ;;
        mov b5 = loc7

        /*
         * Restore predicate registers
         */
        ld8 loc2 = [in0], 16    ;;
        mov pr = loc2, ~0
        
        /*
         * Restore floating-point registers.
         */
        ldf.fill f2 = [in0], 16 ;;
        ldf.fill f3 = [in0], 16 ;;
        ldf.fill f4 = [in0], 16 ;;
        ldf.fill f5 = [in0], 16 ;;

        ldf.fill f16 = [in0], 16 ;;
        ldf.fill f17 = [in0], 16 ;;
        ldf.fill f18 = [in0], 16 ;;
        ldf.fill f19 = [in0], 16 ;;
        ldf.fill f20 = [in0], 16 ;;
        ldf.fill f21 = [in0], 16 ;;
        ldf.fill f22 = [in0], 16 ;;
        ldf.fill f23 = [in0], 16 ;;
        ldf.fill f24 = [in0], 16 ;;
        ldf.fill f25 = [in0], 16 ;;
        ldf.fill f26 = [in0], 16 ;;
        ldf.fill f27 = [in0], 16 ;;
        ldf.fill f28 = [in0], 16 ;;
        ldf.fill f29 = [in0], 16 ;;
        ldf.fill f30 = [in0], 16 ;;
        ldf.fill f31 = [in0], 16 ;;
        
        mov ar.unat = loc1
        
        mov r8 = r0                     /* context_restore returns 0 */
        br.ret.sptk.many b0