/**

 * $Id$

 * 

 * Provides the implementation for the AMD64 ABI (eg prologue, epilogue, and

 * calling conventions)

 *

 * Copyright (c) 2007 Nathan Keynes.

 *

 * 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 of the License, 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.

 */

#define REG_ARG1 REG_RDI

#define REG_ARG2 REG_RSI

#define REG_ARG3 REG_RDX

#define REG_RESULT1 REG_RAX

#define MAX_REG_ARG 3  /* There's more, but we don't use more than 3 here anyway */

#define REG_SAVE1 REG_R12

#define REG_SAVE2 REG_R13

#define REG_SAVE3 REG_R14

#define REG_SAVE4 REG_R15

#define REG_CALLPTR REG_EBX

static inline void decode_address( uintptr_t base, int addr_reg, int target_reg )

{

    MOVL_r32_r32( addr_reg, target_reg );

    SHRL_imm_r32( 12, target_reg );

    MOVP_immptr_rptr( base, REG_RDI );

    MOVP_sib_rptr( 3, target_reg, REG_RDI, 0, target_reg );

}

/**

 * Note: clobbers ECX to make the indirect call - this isn't usually

 * a problem since the callee will generally clobber it anyway.

 * Size: 12 bytes

 */

static inline void CALL_ptr( void *ptr )

{

    MOVP_immptr_rptr( (uintptr_t)ptr, REG_ECX );

    CALL_r32(REG_ECX);

}

#define CALL1_PTR_MIN_SIZE 12

static inline void CALL1_ptr_r32( void *ptr, int arg1 )

{

    if( arg1 != REG_ARG1 ) {

        MOVQ_r64_r64( arg1, REG_ARG1 );

    }

    CALL_ptr(ptr);

}

static inline void CALL1_r32disp_r32( int preg, uint32_t disp, int arg1 )

{

    if( arg1 != REG_ARG1 ) {

        MOVQ_r64_r64( arg1, REG_ARG1 );

    }

    CALL_r32disp(preg, disp);    

}

static inline void CALL2_ptr_r32_r32( void *ptr, int arg1, int arg2 )

{

    if( arg2 != REG_ARG2 ) {

        MOVQ_r64_r64( arg2, REG_ARG2 );

    }

    if( arg1 != REG_ARG1 ) {

        MOVQ_r64_r64( arg1, REG_ARG1 );

    }

    CALL_ptr(ptr);

}

static inline void CALL2_r32disp_r32_r32( int preg, uint32_t disp, int arg1, int arg2 )

{

    if( arg2 != REG_ARG2 ) {

        MOVQ_r64_r64( arg2, REG_ARG2 );

    }

    if( arg1 != REG_ARG1 ) {

        MOVQ_r64_r64( arg1, REG_ARG1 );

    }

    CALL_r32disp(preg, disp);    

}

static inline void CALL3_r32disp_r32_r32_r32( int preg, uint32_t disp, int arg1, int arg2, int arg3 )

{

    if( arg3 != REG_ARG3 ) {

        MOVQ_r64_r64( arg3, REG_ARG3 );

    }

    if( arg2 != REG_ARG2 ) {

        MOVQ_r64_r64( arg2, REG_ARG2 );

    }

    if( arg1 != REG_ARG1 ) {

        MOVQ_r64_r64( arg1, REG_ARG1 );

    }

    CALL_r32disp(preg, disp);    

}

#define PROLOGUE_SIZE 15

/**

 * Emit the 'start of block' assembly. Sets up the stack frame and save

 * SI/DI as required

 */

static inline void emit_prologue( )

{

    PUSH_r32(REG_RBP);

    SUBQ_imms_r64( 16, REG_RSP ); 

    MOVP_immptr_rptr( ((uint8_t *)&sh4r) + 128, REG_EBP );

}

static inline void emit_epilogue( )

{

    ADDQ_imms_r64( 16, REG_RSP );

    POP_r32(REG_RBP);

}