vfpundef.c

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/*
 * vfpundef.c
 * VFP UNDEF handler
 * called _after_ the top-level UNDEF handler has:
 * saved registers, switched mode, and identified CP10,11 bounce.
 * Copyright (C) ARM Limited, 2002. All rights reserved.
 */

typedef unsigned uint32;
#define IGNORE(x) (void)(x)

#include "slundef.h"
#include "controlbuffer.h"
#include "vfpsubarch.h"

/* this is a non-ATPCS entry point: we only need the address here */
EXTERN_C
void VFP_Computation_Engine_Wrapper(void);

#pragma arm /* force ARM state code */

/* returns the EN bit FPEXC[30] */
__inline int VFP_Is_Enabled(void)
{
    int x;
    /* FMRX x, FPEXC */
    __asm { MRC p10, 7, x, c8, c0, 0 }
    return ((x & /* EN bit */(1 << 30)) != 0);
}

__value_in_regs
HandlerReturnType VFP_Undef_Handler(uint32 instr, ARM_RegDump *regdump)
{
    ControlBuffer *controlbuffer;
    _VFP_Computation_Description *desc;
    uint32 skip_instr;

    if (!VFP_Is_Enabled())
        /* Replace this with jump to lazy context switch code */
        return Unknown_Coproc_Handler(instr, regdump);

    if (!_VFP_Is_Compute_Exception(instr))
        return Unknown_Coproc_Handler(instr, regdump);

    /* Find a controlbuffer for a user-level exception */
    controlbuffer =
        GetControlBuffer(regdump,
                         &VFP_Computation_Engine_Wrapper,
                         sizeof(_VFP_Computation_Description));
    desc = (_VFP_Computation_Description *)&controlbuffer->data;

    /* Fill out the _VFP_Computation_Description */
    skip_instr =
        _VFP_Collect_Trap_Description(desc, instr);

    /* and return to the top-level handler */
    {
        HandlerReturnType ret;
        ret.skip_instr = skip_instr;
        ret.controlbuffer = controlbuffer;
        return ret;
    }
}


/* end of vfpundef.c */