nlrx86.c
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/*
* 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/mpconfig.h"
#include "py/mpstate.h"
#include "py/nlr.h"
#if !MICROPY_NLR_SETJMP && defined(__i386__)
#undef nlr_push
// For reference, x86 callee save regs are:
// ebx, esi, edi, ebp, esp, eip
#define NLR_OS_WINDOWS (defined(_WIN32) || defined(__CYGWIN__))
#if 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
unsigned int nlr_push(nlr_buf_t *nlr) {
(void)nlr;
__asm volatile (
// Check for Zephyr, which uses a different calling convention
// by default.
// TODE: Better support for various x86 calling conventions
// (unfortunately, __attribute__((naked)) is not supported on x86).
#ifndef __ZEPHYR__
"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
);
return 0; // needed to silence compiler warning
}
__attribute__((used)) unsigned int nlr_push_tail(nlr_buf_t *nlr) {
nlr_buf_t **top = &MP_STATE_THREAD(nlr_top);
nlr->prev = *top;
*top = nlr;
return 0; // normal return
}
void nlr_pop(void) {
nlr_buf_t **top = &MP_STATE_THREAD(nlr_top);
*top = (*top)->prev;
}
NORETURN void nlr_jump(void *val) {
nlr_buf_t **top_ptr = &MP_STATE_THREAD(nlr_top);
nlr_buf_t *top = *top_ptr;
if (top == NULL) {
nlr_jump_fail(val);
}
top->ret_val = val;
*top_ptr = top->prev;
__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
);
for (;;); // needed to silence compiler warning
}
#endif // !MICROPY_NLR_SETJMP && defined(__i386__)