newlib-cygwin/newlib/libc/machine/spu/spu_timer_flih.S

/*
(C) Copyright IBM Corp. 2008

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AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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*/

/*  First-level interrupt handler.  */

/* The following two convenience macros assist in the coding of the
   saving and restoring the volatile register starting from register
   2 up to register 79.

   saveregs     first, last    Saves registers from first to the last.
   restoreregs  first, last    Restores registers from last down to first.

   Note:       first must be less than or equal to last.  */

.macro  saveregs        first, last
	stqd            $\first, -(STACK_SKIP+\first)*16($SP)
.if     \last-\first
	saveregs        "(\first+1)",\last
.endif
.endm


.macro  restoreregs     first, last
	lqd             $\last, (82-\last)*16($SP)
.if     \last-\first
	restoreregs     \first,"(\last-1)"
.endif
.endm

	.section        .interrupt,"ax"
	.align          3
	.type           spu_flih, @function
spu_flih:
	/* Adjust the stack pointer to skip the maximum register save area
	   (STACK_SKIP quadword registers) in case an interrupt occurred while
	   executing a leaf function that used the stack area without actually
	   allocating its own stack frame.  */
	.set            STACK_SKIP, 125

	/* Save the current link register on a new stack frame for the
	   normal spu_flih() version of this file.  */
	stqd            $0,  -(STACK_SKIP+80)*16($SP)
	stqd            $SP, -(STACK_SKIP+82)*16($SP)   /* Save back chain pointer.  */

	saveregs        2, 39

	il              $2,  -(STACK_SKIP+82)*16        /* Stack frame size.  */
	rdch            $3, $SPU_RdEventStat            /* Read event status.  */

	rdch            $6, $SPU_RdEventMask            /* Read event mask.  */
	hbrp                                            /* Open a slot for instruction prefetch.  */

	saveregs        40,59

	clz             $4, $3                          /* Get first slih index.  */
	stqd            $6,  -(STACK_SKIP+1)*16($SP)    /* Save event mask on stack.  */

	saveregs        60, 67

	/* Do not disable/ack the decrementer event here.
	   The timer library manages this and expects it
	   to be enabled upon entry to the SLIH. */
	il              $7, 0x20
	andc            $5, $3, $7
	andc            $7, $6, $5                      /* Clear event bits.  */
	saveregs        68, 69

	wrch            $SPU_WrEventAck, $3             /* Ack events(s) - include decrementer event.  */
	wrch            $SPU_WrEventMask, $7            /* Disable event(s) - exclude decrementer event.  */

	saveregs        70, 79

	a               $SP, $SP, $2                    /* Instantiate flih stack frame.  */
next_event:
	/* Fetch and dispatch the event handler for the first non-zero event. The
	   dispatch handler is indexed into the __spu_slih_handlers array using the
	   count of zero off the event status as an index.  */
	ila             $5, __spu_slih_handlers         /* Slih array offset.  */

	shli            $4, $4, 2                       /* Slih entry offset.  */
	lqx             $5, $4, $5                      /* Load slih address.  */
	rotqby          $5, $5, $4                      /* Rotate to word 0.  */
	bisl            $0, $5                          /* Branch to slih.  */

	clz             $4, $3                          /* Get next slih index.  */
	brnz            $3, next_event


	lqd             $2, 81*16($SP)                  /* Read event mask from stack.  */

	restoreregs     40, 79

	wrch            $SPU_WrEventMask, $2            /* Restore event mask.  */
	hbrp                                            /* Open a slot for instruction pre-fetch.  */

	restoreregs     2, 39

	/* Restore the link register from the new stack frame for the
	   normal spu_flih() version of this file.  */
	lqd             $0,  2*16($SP)

	lqd             $SP, 0*16($SP)                 /* restore stack pointer from back chain ptr.  */

	irete                                          /* Return from interrupt and re-enable interrupts.  */
	.size           spu_flih, .-spu_flih
/* spu_slih_handlers[]
   Here we initialize 33 default event handlers.  The first entry in this array
   corresponds to the event handler for the event associated with bit 0 of
   Channel 0 (External Event Status).  The 32nd entry in this array corresponds
   to bit 31 of Channel 0 (DMA Tag Status Update Event).  The 33rd entry in
   this array is a special case entry to handle "phantom events" which occur
   when the channel count for Channel 0 is 1, causing an asynchronous SPU
   interrupt, but the value returned for a read of Channel 0 is 0.  The index
   calculated into this array by spu_flih() for this case is 32, hence the
   33rd entry.  */
.data
	.align  4
	.extern __spu_default_slih
	.global __spu_slih_handlers
	.type   __spu_slih_handlers, @object
__spu_slih_handlers:
	.rept 33
	.long   __spu_default_slih
	.endr
	.size   __spu_slih_handlers, .-__spu_slih_handlers