Edit - switch_amd64

Edit: switch_amd64_unix.h

/*
 * this is the internal transfer function.
 *
 * HISTORY
 * 3-May-13   Ralf Schmitt  <ralf@systemexit.de>
 *     Add support for strange GCC caller-save decisions
 *     (ported from switch_aarch64_gcc.h)
 * 18-Aug-11  Alexey Borzenkov  <snaury@gmail.com>
 *      Correctly save rbp, csr and cw
 * 01-Apr-04  Hye-Shik Chang    <perky@FreeBSD.org>
 *      Ported from i386 to amd64.
 * 24-Nov-02  Christian Tismer  <tismer@tismer.com>
 *      needed to add another magic constant to insure
 *      that f in slp_eval_frame(PyFrameObject *f)
 *      STACK_REFPLUS will probably be 1 in most cases.
 *      gets included into the saved stack area.
 * 17-Sep-02  Christian Tismer  <tismer@tismer.com>
 *      after virtualizing stack save/restore, the
 *      stack size shrunk a bit. Needed to introduce
 *      an adjustment STACK_MAGIC per platform.
 * 15-Sep-02  Gerd Woetzel       <gerd.woetzel@GMD.DE>
 *      slightly changed framework for spark
 * 31-Avr-02  Armin Rigo         <arigo@ulb.ac.be>
 *      Added ebx, esi and edi register-saves.
 * 01-Mar-02  Samual M. Rushing  <rushing@ironport.com>
 *      Ported from i386.
 */

#define STACK_REFPLUS 1

#ifdef SLP_EVAL

/* #define STACK_MAGIC 3 */
/* the above works fine with gcc 2.96, but 2.95.3 wants this */
#define STACK_MAGIC 0

#define REGS_TO_SAVE "r12", "r13", "r14", "r15"

static int
slp_switch(void)
{
    int err;
    void* rbp;
    void* rbx;
    unsigned int csr;
    unsigned short cw;
    /* This used to be declared 'register', but that does nothing in
    modern compilers and is explicitly forbidden in some new
    standards. */
    long *stackref, stsizediff;
    __asm__ volatile ("" : : : REGS_TO_SAVE);
    __asm__ volatile ("fstcw %0" : "=m" (cw));
    __asm__ volatile ("stmxcsr %0" : "=m" (csr));
    __asm__ volatile ("movq %%rbp, %0" : "=m" (rbp));
    __asm__ volatile ("movq %%rbx, %0" : "=m" (rbx));
    __asm__ ("movq %%rsp, %0" : "=g" (stackref));
    {
        SLP_SAVE_STATE(stackref, stsizediff);
        __asm__ volatile (
            "addq %0, %%rsp\n"
            "addq %0, %%rbp\n"
            :
            : "r" (stsizediff)
            );
        SLP_RESTORE_STATE();
        __asm__ volatile ("xorq %%rax, %%rax" : "=a" (err));
    }
    __asm__ volatile ("movq %0, %%rbx" : : "m" (rbx));
    __asm__ volatile ("movq %0, %%rbp" : : "m" (rbp));
    __asm__ volatile ("ldmxcsr %0" : : "m" (csr));
    __asm__ volatile ("fldcw %0" : : "m" (cw));
    __asm__ volatile ("" : : : REGS_TO_SAVE);
    return err;
}

#endif

/*
 * further self-processing support
 */

/*
 * if you want to add self-inspection tools, place them
 * here. See the x86_msvc for the necessary defines.
 * These features are highly experimental und not
 * essential yet.
 */

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