circuitpython/py/nlrx64.c

/*
 * 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"
#include "py/nlr.h"

#if !MICROPY_NLR_SETJMP && defined(__x86_64__)

#undef nlr_push

// x86-64 callee-save registers are:
//  rbx, rbp, rsp, r12, r13, r14, r15

#if defined(_WIN32) || defined(__CYGWIN__)
#define NLR_OS_WINDOWS 1
#else
#define NLR_OS_WINDOWS 0
#endif

__attribute__((used)) unsigned int nlr_push_tail(nlr_buf_t *nlr);

unsigned int nlr_push(nlr_buf_t *nlr) {
    (void)nlr;

    #if NLR_OS_WINDOWS

    __asm volatile (
    "movq   (%rsp), %rax        \n" // load return %rip
    "movq   %rax, 16(%rcx)      \n" // store %rip into nlr_buf
    "movq   %rbp, 24(%rcx)      \n" // store %rbp into nlr_buf
    "movq   %rsp, 32(%rcx)      \n" // store %rsp into nlr_buf
    "movq   %rbx, 40(%rcx)      \n" // store %rbx into nlr_buf
    "movq   %r12, 48(%rcx)      \n" // store %r12 into nlr_buf
    "movq   %r13, 56(%rcx)      \n" // store %r13 into nlr_buf
    "movq   %r14, 64(%rcx)      \n" // store %r14 into nlr_buf
    "movq   %r15, 72(%rcx)      \n" // store %r15 into nlr_buf
    "movq   %rdi, 80(%rcx)      \n" // store %rdr into nlr_buf
    "movq   %rsi, 88(%rcx)      \n" // store %rsi into nlr_buf
    "jmp    nlr_push_tail       \n" // do the rest in C
    );

    #else

    __asm volatile (
    #if defined(__APPLE__) || defined(__MACH__)
    "pop    %rbp                \n" // undo function's prelude
    #endif
    "movq   (%rsp), %rax        \n" // load return %rip
    "movq   %rax, 16(%rdi)      \n" // store %rip into nlr_buf
    "movq   %rbp, 24(%rdi)      \n" // store %rbp into nlr_buf
    "movq   %rsp, 32(%rdi)      \n" // store %rsp into nlr_buf
    "movq   %rbx, 40(%rdi)      \n" // store %rbx into nlr_buf
    "movq   %r12, 48(%rdi)      \n" // store %r12 into nlr_buf
    "movq   %r13, 56(%rdi)      \n" // store %r13 into nlr_buf
    "movq   %r14, 64(%rdi)      \n" // store %r14 into nlr_buf
    "movq   %r15, 72(%rdi)      \n" // store %r15 into nlr_buf
    #if defined(__APPLE__) || defined(__MACH__)
    "jmp    _nlr_push_tail      \n" // do the rest in C
    #else
    "jmp    nlr_push_tail       \n" // do the rest in C
    #endif
    );

    #endif

    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 (
    "movq   %0, %%rcx           \n" // %rcx points to nlr_buf
    #if NLR_OS_WINDOWS
    "movq   88(%%rcx), %%rsi    \n" // load saved %rsi
    "movq   80(%%rcx), %%rdi    \n" // load saved %rdr
    #endif
    "movq   72(%%rcx), %%r15    \n" // load saved %r15
    "movq   64(%%rcx), %%r14    \n" // load saved %r14
    "movq   56(%%rcx), %%r13    \n" // load saved %r13
    "movq   48(%%rcx), %%r12    \n" // load saved %r12
    "movq   40(%%rcx), %%rbx    \n" // load saved %rbx
    "movq   32(%%rcx), %%rsp    \n" // load saved %rsp
    "movq   24(%%rcx), %%rbp    \n" // load saved %rbp
    "movq   16(%%rcx), %%rax    \n" // load saved %rip
    "movq   %%rax, (%%rsp)      \n" // store saved %rip to stack
    "xorq   %%rax, %%rax        \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(__x86_64__)