/**

 * $Id$

 * 

 * Provides the implementation for the ia32 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.

 */

#ifndef __lxdream_ia32abi_H

#define __lxdream_ia32abi_H 1

#define load_ptr( reg, ptr ) load_imm32( reg, (uint32_t)ptr );

/**

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

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

 */

#define CALL_FUNC0_SIZE 13

static inline void call_func0( void *ptr )

{

    int adj = (-sh4_x86.stack_posn)&0x0F;

    SUB_imm8s_r32( adj, R_ESP );

    load_imm32(R_EAX, (uint32_t)ptr);

    CALL_r32(R_EAX);

    ADD_imm8s_r32( adj, R_ESP );

}

#define CALL_FUNC1_SIZE 14

static inline void call_func1( void *ptr, int arg1 )

{

    int adj = (-4-sh4_x86.stack_posn)&0x0F;

    SUB_imm8s_r32( adj, R_ESP );

    PUSH_r32(arg1);

    load_imm32(R_EAX, (uint32_t)ptr);

    CALL_r32(R_EAX);

    ADD_imm8s_r32( adj+4, R_ESP );

    sh4_x86.stack_posn -= 4;

}

#define CALL_FUNC2_SIZE 15

static inline void call_func2( void *ptr, int arg1, int arg2 )

{

    int adj = (-8-sh4_x86.stack_posn)&0x0F;

    SUB_imm8s_r32( adj, R_ESP );

    PUSH_r32(arg2);

    PUSH_r32(arg1);

    load_imm32(R_EAX, (uint32_t)ptr);

    CALL_r32(R_EAX);

    ADD_imm8s_r32( adj+8, R_ESP );

    sh4_x86.stack_posn -= 8;

}

/**

 * Write a double (64-bit) value into memory, with the first word in arg2a, and

 * the second in arg2b

 * NB: 30 bytes

 */

#define MEM_WRITE_DOUBLE_SIZE 36

static inline void MEM_WRITE_DOUBLE( int addr, int arg2a, int arg2b )

{

    int adj = (-8-sh4_x86.stack_posn)&0x0F;

    SUB_imm8s_r32( adj, R_ESP );

    ADD_imm8s_r32( 4, addr );

    PUSH_r32(arg2b);

    PUSH_r32(addr);

    ADD_imm8s_r32( -4, addr );

    SUB_imm8s_r32( 8, R_ESP );

    PUSH_r32(arg2a);

    PUSH_r32(addr);

    load_imm32(R_EAX, (uint32_t)sh4_write_long);

    CALL_r32(R_EAX);

    ADD_imm8s_r32( 16, R_ESP );

    load_imm32(R_EAX, (uint32_t)sh4_write_long);

    CALL_r32(R_EAX);

    ADD_imm8s_r32( adj+8, R_ESP );

    sh4_x86.stack_posn -= 16;

}

/**

 * Read a double (64-bit) value from memory, writing the first word into arg2a

 * and the second into arg2b. The addr must not be in EAX

 * NB: 27 bytes

 */

#define MEM_READ_DOUBLE_SIZE 36

static inline void MEM_READ_DOUBLE( int addr, int arg2a, int arg2b )

{

    int adj = (-4-sh4_x86.stack_posn)&0x0F;

    int adj2 = (-8-sh4_x86.stack_posn)&0x0F;

    SUB_imm8s_r32( adj, R_ESP );

    PUSH_r32(addr);

    load_imm32(R_EAX, (uint32_t)sh4_read_long);

    CALL_r32(R_EAX);

    POP_r32(addr);

    SUB_imm8s_r32( adj2-adj, R_ESP );

    PUSH_r32(R_EAX);

    ADD_imm8s_r32( 4, addr );

    PUSH_r32(addr);

    load_imm32(R_EAX, (uint32_t)sh4_read_long);

    CALL_r32(R_EAX);

    ADD_imm8s_r32( 4, R_ESP );

    MOV_r32_r32( R_EAX, arg2b );

    POP_r32(arg2a);

    ADD_imm8s_r32( adj2, R_ESP );

    sh4_x86.stack_posn -= 4;

}

#define EXIT_BLOCK_SIZE 29

/**

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

 * SI/DI as required

 */

void sh4_translate_begin_block( sh4addr_t pc ) 

{

    PUSH_r32(R_EBP);

    /* mov &sh4r, ebp */

    load_ptr( R_EBP, &sh4r );

    sh4_x86.in_delay_slot = FALSE;

    sh4_x86.priv_checked = FALSE;

    sh4_x86.fpuen_checked = FALSE;

    sh4_x86.branch_taken = FALSE;

    sh4_x86.backpatch_posn = 0;

    sh4_x86.block_start_pc = pc;

    sh4_x86.tstate = TSTATE_NONE;

    sh4_x86.stack_posn = 8;

}

/**

 * Exit the block with sh4r.pc already written

 * Bytes: 15

 */

void exit_block_pcset( pc )

{

    load_imm32( R_ECX, ((pc - sh4_x86.block_start_pc)>>1)*sh4_cpu_period ); // 5

    ADD_r32_sh4r( R_ECX, REG_OFFSET(slice_cycle) );    // 6

    load_spreg( R_EAX, REG_OFFSET(pc) );

    call_func1(xlat_get_code,R_EAX);

    POP_r32(R_EBP);

    RET();

}

/**

 * Exit the block to an absolute PC

 */

void exit_block( sh4addr_t pc, sh4addr_t endpc )

{

    load_imm32( R_ECX, pc );                            // 5

    store_spreg( R_ECX, REG_OFFSET(pc) );               // 3

    MOV_moff32_EAX( xlat_get_lut_entry(pc) ); // 5

    AND_imm8s_r32( 0xFC, R_EAX ); // 3

    load_imm32( R_ECX, ((endpc - sh4_x86.block_start_pc)>>1)*sh4_cpu_period ); // 5

    ADD_r32_sh4r( R_ECX, REG_OFFSET(slice_cycle) );     // 6

    POP_r32(R_EBP);

    RET();

}

/**

 * Write the block trailer (exception handling block)

 */

void sh4_translate_end_block( sh4addr_t pc ) {

    if( sh4_x86.branch_taken == FALSE ) {

	// Didn't exit unconditionally already, so write the termination here

	exit_block( pc, pc );

    }

    if( sh4_x86.backpatch_posn != 0 ) {

	unsigned int i;

	// Raise exception

	uint8_t *end_ptr = xlat_output;

	load_spreg( R_ECX, REG_OFFSET(pc) );

	ADD_r32_r32( R_EDX, R_ECX );

	ADD_r32_r32( R_EDX, R_ECX );

	store_spreg( R_ECX, REG_OFFSET(pc) );

	MOV_moff32_EAX( &sh4_cpu_period );

	MUL_r32( R_EDX );

	ADD_r32_sh4r( R_EAX, REG_OFFSET(slice_cycle) );

        POP_r32(R_EDX);

        call_func1( sh4_raise_exception, R_EDX );

	load_spreg( R_EAX, REG_OFFSET(pc) );

	call_func1(xlat_get_code,R_EAX);

	POP_r32(R_EBP);

	RET();

	// Exception already raised - just cleanup

	uint8_t *preexc_ptr = xlat_output;

	load_imm32( R_ECX, sh4_x86.block_start_pc );

	ADD_r32_r32( R_EDX, R_ECX );

	ADD_r32_r32( R_EDX, R_ECX );

	store_spreg( R_ECX, REG_OFFSET(spc) );

	MOV_moff32_EAX( &sh4_cpu_period );

	MUL_r32( R_EDX );

	ADD_r32_sh4r( R_EAX, REG_OFFSET(slice_cycle) );

	load_spreg( R_EAX, REG_OFFSET(pc) );

	call_func1(xlat_get_code,R_EAX);

	POP_r32(R_EBP);

	RET();

	for( i=0; i< sh4_x86.backpatch_posn; i++ ) {

	    *sh4_x86.backpatch_list[i].fixup_addr =

		xlat_output - ((uint8_t *)sh4_x86.backpatch_list[i].fixup_addr) - 4;

	    if( sh4_x86.backpatch_list[i].exc_code == -1 ) {

		load_imm32( R_EDX, sh4_x86.backpatch_list[i].fixup_icount );

		int rel = preexc_ptr - xlat_output;

		JMP_rel(rel);

	    } else {

		PUSH_imm32( sh4_x86.backpatch_list[i].exc_code );

		load_imm32( R_EDX, sh4_x86.backpatch_list[i].fixup_icount );

		int rel = end_ptr - xlat_output;

		JMP_rel(rel);

	    }

	}

    }

}

#endif