/**

 * $Id$

 * 

 * 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 7

static inline void call_func0( void *ptr )

{

    load_imm32(R_EAX, (uint32_t)ptr);

    CALL_r32(R_EAX);

}

#define CALL_FUNC1_SIZE 11

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

{

    PUSH_r32(arg1);

    call_func0(ptr);

    ADD_imm8s_r32( 4, R_ESP );

}

#define CALL_FUNC2_SIZE 12

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

{

    PUSH_r32(arg2);

    PUSH_r32(arg1);

    call_func0(ptr);

    ADD_imm8s_r32( 8, R_ESP );

}

/**

 * 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 30

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

{

    ADD_imm8s_r32( 4, addr );

    PUSH_r32(arg2b);

    PUSH_r32(addr);

    ADD_imm8s_r32( -4, addr );

    PUSH_r32(arg2a);

    PUSH_r32(addr);

    call_func0(sh4_write_long);

    ADD_imm8s_r32( 8, R_ESP );

    call_func0(sh4_write_long);

    ADD_imm8s_r32( 8, R_ESP );

}

/**

 * 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 27

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

{

    PUSH_r32(addr);

    call_func0(sh4_read_long);

    POP_r32(R_ECX);

    PUSH_r32(R_EAX);

    ADD_imm8s_r32( 4, R_ECX );

    PUSH_r32(R_ECX);

    call_func0(sh4_read_long);

    ADD_imm8s_r32( 4, R_ESP );

    MOV_r32_r32( R_EAX, arg2b );

    POP_r32(arg2a);

}

/**

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

    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.tlb_on = IS_MMU_ENABLED();

    sh4_x86.tstate = TSTATE_NONE;

#ifdef STACK_ALIGN

    sh4_x86.stack_posn = 8;

#endif

}

/**

 * Exit the block with sh4r.pc already written

 */

void exit_block_pcset( sh4addr_t 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, R_PC );

    if( sh4_x86.tlb_on ) {

        call_func1(xlat_get_code_by_vma,R_EAX);

    } else {

        call_func1(xlat_get_code,R_EAX);

    } 

    POP_r32(R_EBP);

    RET();

}

/**

 * Exit the block with sh4r.new_pc written with the target pc

 */

void exit_block_newpcset( sh4addr_t 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, R_NEW_PC );

    store_spreg( R_EAX, R_PC );

    if( sh4_x86.tlb_on ) {

        call_func1(xlat_get_code_by_vma,R_EAX);

    } else {

        call_func1(xlat_get_code,R_EAX);

    } 

    POP_r32(R_EBP);

    RET();

}

#define EXIT_BLOCK_SIZE(pc)  (24 + (IS_IN_ICACHE(pc)?5:CALL_FUNC1_SIZE))

/**

 * 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

    if( IS_IN_ICACHE(pc) ) {

        MOV_moff32_EAX( xlat_get_lut_entry(GET_ICACHE_PHYS(pc)) ); // 5

    } else if( sh4_x86.tlb_on ) {

        call_func1(xlat_get_code_by_vma,R_ECX);

    } else {

        call_func1(xlat_get_code,R_ECX);

    }

    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();

}

#define EXIT_BLOCK_REL_SIZE(pc)  (27 + (IS_IN_ICACHE(pc)?5:CALL_FUNC1_SIZE))

/**

 * Exit the block to a relative PC

 */

void exit_block_rel( sh4addr_t pc, sh4addr_t endpc )

{

    load_imm32( R_ECX, pc - sh4_x86.block_start_pc );   // 5

    ADD_sh4r_r32( R_PC, R_ECX );

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

    if( IS_IN_ICACHE(pc) ) {

        MOV_moff32_EAX( xlat_get_lut_entry(GET_ICACHE_PHYS(pc)) ); // 5

    } else if( sh4_x86.tlb_on ) {

        call_func1(xlat_get_code_by_vma,R_ECX);

    } else {

        call_func1(xlat_get_code,R_ECX);

    }

    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_rel( pc, pc );

    }

    if( sh4_x86.backpatch_posn != 0 ) {

        unsigned int i;

        // Raise exception

        uint8_t *end_ptr = xlat_output;

        MOV_r32_r32( R_EDX, R_ECX );

        ADD_r32_r32( R_EDX, R_ECX );

        ADD_r32_sh4r( R_ECX, R_PC );

        MOV_moff32_EAX( &sh4_cpu_period );

        MUL_r32( R_EDX );

        ADD_r32_sh4r( R_EAX, REG_OFFSET(slice_cycle) );

        call_func0( sh4_raise_exception );

        ADD_imm8s_r32( 4, R_ESP );

        load_spreg( R_EAX, R_PC );

        if( sh4_x86.tlb_on ) {

            call_func1(xlat_get_code_by_vma,R_EAX);

        } else {

            call_func1(xlat_get_code,R_EAX);

        }

        POP_r32(R_EBP);

        RET();

        // Exception already raised - just cleanup

        uint8_t *preexc_ptr = xlat_output;

        MOV_r32_r32( R_EDX, R_ECX );

        ADD_r32_r32( R_EDX, R_ECX );

        ADD_r32_sh4r( R_ECX, R_SPC );

        MOV_moff32_EAX( &sh4_cpu_period );

        MUL_r32( R_EDX );

        ADD_r32_sh4r( R_EAX, REG_OFFSET(slice_cycle) );

        load_spreg( R_EAX, R_PC );

        if( sh4_x86.tlb_on ) {

            call_func1(xlat_get_code_by_vma,R_EAX);

        } else {

            call_func1(xlat_get_code,R_EAX);

        }

        POP_r32(R_EBP);

        RET();

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

            uint32_t *fixup_addr = (uint32_t *)&xlat_current_block->code[sh4_x86.backpatch_list[i].fixup_offset];

            *fixup_addr = xlat_output - (uint8_t *)&xlat_current_block->code[sh4_x86.backpatch_list[i].fixup_offset] - 4;

            if( sh4_x86.backpatch_list[i].exc_code < 0 ) {

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

                int stack_adj = -1 - sh4_x86.backpatch_list[i].exc_code;

                if( stack_adj > 0 ) { 

                    ADD_imm8s_r32( stack_adj, R_ESP );

                }

                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);

            }

        }

    }

}

void *xlat_get_native_pc()

{

    void *result = NULL;

    asm(

        "mov %%ebp, %%eax\n\t"

        "mov $0x8, %%ecx\n\t"

        "mov %1, %%edx\n"

        "frame_loop: test %%eax, %%eax\n\t"

        "je frame_not_found\n\t"

        "cmp (%%eax), %%edx\n\t"

        "je frame_found\n\t"

        "sub $0x1, %%ecx\n\t"

        "je frame_not_found\n\t"

        "movl (%%eax), %%eax\n\t"

        "jmp frame_loop\n"

        "frame_found: movl 0x4(%%eax), %0\n"

        "frame_not_found:"

        : "=r" (result)

        : "r" (((uint8_t *)&sh4r) + 128 )

        : "eax", "ecx", "edx" );

    return result;

}

#endif /* !lxdream_ia32abi_H */