/*
 * This file is part of the MicroPython project, http://micropython.org/
 *
 * The MIT License (MIT)
 *
 * Copyright (c) 2013-2017 Damien P. George
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */

#include "py/mpstate.h"

#if MICROPY_NLR_X86

#undef nlr_push

// For reference, x86 callee save regs are:
// ebx, esi, edi, ebp, esp, eip

#if MICROPY_NLR_OS_WINDOWS
unsigned int nlr_push_tail(nlr_buf_t *nlr) asm ("nlr_push_tail");
#else
__attribute__((used)) unsigned int nlr_push_tail(nlr_buf_t *nlr);
#endif

#if !defined(__clang__) && defined(__GNUC__) && __GNUC__ >= 8
// Since gcc 8.0 the naked attribute is supported
#define USE_NAKED (1)
#define UNDO_PRELUDE (0)
#elif defined(__ZEPHYR__) || defined(__ANDROID__)
// Zephyr and Android use a different calling convention by default
#define USE_NAKED (0)
#define UNDO_PRELUDE (0)
#else
#define USE_NAKED (0)
#define UNDO_PRELUDE (1)
#endif

#if USE_NAKED
__attribute__((naked))
#endif
unsigned int nlr_push(nlr_buf_t *nlr) {
 (void)nlr;

 __asm volatile (
 #if UNDO_PRELUDE
 "pop %ebp \n" // undo function's prelude
 #endif
 "mov 4(%esp), %edx \n" // load nlr_buf
 "mov (%esp), %eax \n" // load return %eip
 "mov %eax, 8(%edx) \n" // store %eip into nlr_buf
 "mov %ebp, 12(%edx) \n" // store %ebp into nlr_buf
 "mov %esp, 16(%edx) \n" // store %esp into nlr_buf
 "mov %ebx, 20(%edx) \n" // store %ebx into nlr_buf
 "mov %edi, 24(%edx) \n" // store %edi into nlr_buf
 "mov %esi, 28(%edx) \n" // store %esi into nlr_buf
 "jmp nlr_push_tail \n" // do the rest in C
 );

 #if !USE_NAKED
 return 0; // needed to silence compiler warning
 #endif
}

NORETURN void nlr_jump(void *val) {
 MP_NLR_JUMP_HEAD(val, top)

 __asm volatile (
 "mov %0, %%edx \n" // %edx points to nlr_buf
 "mov 28(%%edx), %%esi \n" // load saved %esi
 "mov 24(%%edx), %%edi \n" // load saved %edi
 "mov 20(%%edx), %%ebx \n" // load saved %ebx
 "mov 16(%%edx), %%esp \n" // load saved %esp
 "mov 12(%%edx), %%ebp \n" // load saved %ebp
 "mov 8(%%edx), %%eax \n" // load saved %eip
 "mov %%eax, (%%esp) \n" // store saved %eip to stack
 "xor %%eax, %%eax \n" // clear return register
 "inc %%al \n" // increase to make 1, non-local return
 "ret \n" // return
 : // output operands
 : "r" (top) // input operands
 : // clobbered registers
 );

 MP_UNREACHABLE
}

#endif // MICROPY_NLR_X86