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/*
* this is the internal transfer function.
*
* HISTORY
* 30-Aug-13 Floris Bruynooghe <flub@devork.be>
Clean the register windows again before returning.
This does not clobber the PIC register as it leaves
the current window intact and is required for multi-
threaded code to work correctly.
* 08-Mar-11 Floris Bruynooghe <flub@devork.be>
* No need to set return value register explicitly
* before the stack and framepointer are adjusted
* as none of the other registers are influenced by
* this. Also don't needlessly clean the windows
* ('ta %0" :: "i" (ST_CLEAN_WINDOWS)') as that
* clobbers the gcc PIC register (%l7).
* 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>
* added support for SunOS sparc with gcc
*/
#define STACK_REFPLUS 1
#ifdef SLP_EVAL
#define STACK_MAGIC 0
#define ST_FLUSH_WINDOWS 0x03
#define ST_CLEAN_WINDOWS 0x04
static int
slp_switch(void)
{
register int *stackref, stsizediff;
/* Flush SPARC register windows onto the stack, so they can be used to
* restore the registers after the stack has been switched out and
* restored. This also ensures the current window (pointed at by
* the CWP register) is the only window left in the registers
* (CANSAVE=0, CANRESTORE=0), that means the registers of our
* caller are no longer there and when we return they will always
* be loaded from the stack by a window underflow/fill trap.
*
* On SPARC v9 and above it might be more efficient to use the
* FLUSHW instruction instead of TA ST_FLUSH_WINDOWS. But that
* requires the correct -mcpu flag to gcc.
*
* Then put the stack pointer into stackref. */
__asm__ volatile (
"ta %1\n\t"
"mov %%sp, %0"
: "=r" (stackref) : "i" (ST_FLUSH_WINDOWS));
{
/* Thou shalt put SLP_SAVE_STATE into a local block */
/* Copy the current stack onto the heap */
SLP_SAVE_STATE(stackref, stsizediff);
/* Increment stack and frame pointer by stsizediff */
__asm__ volatile (
"add %0, %%sp, %%sp\n\t"
"add %0, %%fp, %%fp"
: : "r" (stsizediff));
/* Copy new stack from it's save store on the heap */
SLP_RESTORE_STATE();
/* No need to set the return value register, the return
* statement below does this just fine. After returning a restore
* instruction is given and a fill-trap will load all the registers
* from the stack if needed. However in a multi-threaded environment
* we can't guarantee the other register windows are fine to use by
* their threads anymore, so tell the CPU to clean them. */
__asm__ volatile ("ta %0" : : "i" (ST_CLEAN_WINDOWS));
return 0;
}
}
#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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