md.hpp

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/* src/vm/jit/sparc64/md.cpp - machine dependent SPARC64 functions

   Copyright (C) 1996-2013
   CACAOVM - Verein zur Foerderung der freien virtuellen Maschine CACAO

   This file is part of CACAO.

   This program is free software; you can redistribute it and/or
   modify it under the terms of the GNU General Public License as
   published by the Free Software Foundation; either version 2, or (at
   your option) any later version.

   This program is distributed in the hope that it will be useful, but
   WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
   02110-1301, USA.

*/


#ifndef VM_JIT_SPARC64_MD_HPP_
#define VM_JIT_SPARC64_MD_HPP_ 1

#include "config.h"

#include <cassert>
#include <stdint.h>

#include "vm/types.hpp"
#include "vm/jit/code.hpp"
#include "vm/jit/codegen-common.hpp"


/**
 * Returns the size (in bytes) of the current stackframe, specified by
 * the passed codeinfo structure.
 */
inline static int32_t md_stacktrace_get_framesize(codeinfo* code)
{
    // Check for the asm_vm_call_method special case.
    if (code == NULL)
        return 0;

    // On SPARC we use 8-byte stackslots.
#error Verify the below line, then remove this error!
    return code->stackframesize * 8;
}


/* md_stacktrace_get_returnaddress *********************************************

   Returns the return address of the current stackframe, specified by
   the passed stack pointer and the stack frame size.

*******************************************************************************/

inline static void *md_stacktrace_get_returnaddress(void *sp, int32_t stackframesize)
{
    void *ra;

    /* flush register windows to the stack */
    __asm__ ("flushw");

    /* the return address resides in register i7, the last register in the
     * 16-extended-word save area
     */
    ra = *((void **) (((uintptr_t) sp) + 120 + BIAS));
    
    /* NOTE: on SPARC ra is the address of the call instruction */

    return ra;
}

inline static void *md_get_framepointer(void *sp)
{
    void *fp;

    /* flush register windows to the stack */
    __asm__ ("flushw");

    fp = *((void **) (((uintptr_t) sp) + 112 + BIAS));

    return fp;
}

inline static void *md_get_pv_from_stackframe(void *sp)
{
    void *pv;

    /* flush register windows to the stack */
    __asm__ ("flushw");

    pv = *((void **) (((uintptr_t) sp) + 104 + BIAS));

    return pv;
}


/* md_codegen_get_pv_from_pc ***************************************************

   This reconstructs and returns the PV of a method given a return address
   pointer. (basically, same was as the generated code following the jump does)
   
   Machine code:

   6b5b4000    jmpl    (pv)
   10000000    nop
   277afffe    ldah    pv,-2(ra)
   237ba61c    lda     pv,-23012(pv)

*******************************************************************************/

/* TODO Move these macros into the code generator. */

/* shift away 13-bit immediate,  mask rd and rs1    */
#define SHIFT_AND_MASK(instr) \
    ((instr >> 13) & 0x60fc1)

/* NOP is defined as a SETHI instruction with rd and imm. set to zero */
/* therefore we check if the 22-bit immediate is zero */
#define IS_SETHI(instr) \
    (((instr & 0xc1c00000)  == 0x01000000) \
    && ((instr & 0x3fffff) != 0x0))

inline s2 decode_13bit_imm(u4 instr) {
    s2 imm;

    /* mask everything else in the instruction */
    imm = instr & 0x00001fff;

    /* sign extend 13-bit to 16-bit */
    imm <<= 3;
    imm >>= 3;

    return imm;
}

inline static void *md_codegen_get_pv_from_pc(void *ra)
{
    uint8_t *pv;
    u8  mcode;
    s4  offset;

    pv = ra;

    /* get the instruction word after jump and nop */
    mcode = *((u4 *) (ra+8) );

    /* check if we have a sethi insruction */
    if (IS_SETHI(mcode)) {
        s4 xor_imm;
                
        /* get 22-bit immediate of sethi instruction */
        offset = (s4) (mcode & 0x3fffff);
        offset = offset << 10;
        
        /* now the xor */
        mcode = *((u4 *) (ra+12) );
        xor_imm = decode_13bit_imm(mcode);
        
        offset ^= xor_imm;   
    }
    else {
        u4 mcode_masked;
        
        mcode_masked = SHIFT_AND_MASK(mcode);

        assert(mcode_masked == 0x40001);

        /* mask and extend the negative sign for the 13 bit immediate */
        offset = decode_13bit_imm(mcode);
    }
    
    pv += offset;

    return pv;
}


/* md_cacheflush ***************************************************************

   Calls the system's function to flush the instruction and data
   cache.

*******************************************************************************/

inline static void md_cacheflush(void *addr, int nbytes)
{
    /* don't know yet */    
}


/* md_dcacheflush **************************************************************

   Calls the system's function to flush the data cache.

*******************************************************************************/

inline static void md_dcacheflush(void *addr, int nbytes)
{
    /* XXX don't know yet */    
    /* printf("md_dcacheflush\n"); */
    __asm__ __volatile__ ( "membar 0x7F" : : : "memory" );
}

#endif // VM_JIT_SPARC64_MD_HPP_


/*
 * These are local overrides for various environment variables in Emacs.
 * Please do not remove this and leave it at the end of the file, where
 * Emacs will automagically detect them.
 * ---------------------------------------------------------------------
 * Local variables:
 * mode: c++
 * indent-tabs-mode: t
 * c-basic-offset: 4
 * tab-width: 4
 * End:
 * vim:noexpandtab:sw=4:ts=4:
 */