/**

  * $Id$

  * 

  * 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.

  */

 static inline void call_func0( void *ptr )

 {

     load_imm32(R_ECX, (uint32_t)ptr);

     CALL_r32(R_ECX);

 }

 #ifdef HAVE_FASTCALL

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

 {

     if( arg1 != R_EAX ) {

         MOV_r32_r32( arg1, R_EAX );

     }

     load_imm32(R_ECX, (uint32_t)ptr);

     CALL_r32(R_ECX);

 }

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

 {

     if( arg2 != R_EDX ) {

         MOV_r32_r32( arg2, R_EDX );

     }

     if( arg1 != R_EAX ) {

         MOV_r32_r32( arg1, R_EAX );

     }

     load_imm32(R_ECX, (uint32_t)ptr);

     CALL_r32(R_ECX);

 }

 /**

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

  * the second in arg2b

  */

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

 {

     PUSH_r32(arg2b);

     PUSH_r32(addr);

     call_func2(sh4_write_long, addr, arg2a);

     POP_r32(R_EAX);

     POP_r32(R_EDX);

     ADD_imm8s_r32(4, R_EAX);

     call_func0(sh4_write_long);

 }

 /**

  * 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

  */

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

 {

     PUSH_r32(addr);

     call_func1(sh4_read_long, addr);

     POP_r32(R_ECX);

     PUSH_r32(R_EAX);

     MOV_r32_r32(R_ECX, R_EAX);

     ADD_imm8s_r32(4, R_EAX);

     call_func0(sh4_read_long);

     if( arg2b != R_EAX ) {

         MOV_r32_r32(R_EAX, arg2b);

     }

     POP_r32(arg2a);

 }

 #else

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

 {

     PUSH_r32(arg1);

     call_func0(ptr);

     ADD_imm8s_r32( 4, R_ESP );

 }

 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

  */

 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

  */

 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);

 }

 #endif

 /**

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

  * SI/DI as required

  */

 void enter_block( ) 

 {

     PUSH_r32(R_EBP);

     /* mov &sh4r, ebp */

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

 #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) );

         POP_r32( R_EAX );

         call_func1( sh4_raise_exception, R_EAX );

         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);

             }

         }

     }

 }

 /**

  * The unwind methods only work if we compiled with DWARF2 frame information

  * (ie -fexceptions), otherwise we have to use the direct frame scan.

  */

 #ifdef HAVE_EXCEPTIONS

 #include <unwind.h>

 struct UnwindInfo {

 	int have_result;

 	void *pc;

 };

 _Unwind_Reason_Code xlat_check_frame( struct _Unwind_Context *context, void *arg )

 {

     void *ebp = (void *)_Unwind_GetGR(context, 5);

     void *expect = (((uint8_t *)&sh4r) + 128 );

 	struct UnwindInfo *info = arg;

     if( ebp == expect ) { 

         info->have_result = 1;

         info->pc = (void *)_Unwind_GetIP(context);

     } else if( info->have_result ) {

         return _URC_NORMAL_STOP;

     }

     return _URC_NO_REASON;

 }

 void *xlat_get_native_pc( void *code, uint32_t code_size )

 {

     struct _Unwind_Exception exc;

     struct UnwindInfo info;

     info.have_result = 0;

     void *result = NULL;

     _Unwind_Backtrace( xlat_check_frame, &info );

     if( info.have_result )

     	return info.pc;

     return NULL;

 }

 #else 

 void *xlat_get_native_pc( void *code, uint32_t code_size )

 {

     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

 #endif /* !lxdream_ia32abi_H */