/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
 * Copyright 2015, Cyril Bur, IBM Corp.
 */

#include "basic_asm.h"
#include "vsx_asm.h"

#long check_vsx(vector int *r3);
#This function wraps storeing VSX regs to the end of an array and a
#call to a comparison function in C which boils down to a memcmp()
FUNC_START(check_vsx)
        PUSH_BASIC_STACK(32)
        std     r3,STACK_FRAME_PARAM(0)(sp)
        addi r3, r3, 16 * 12 #Second half of array
        bl store_vsx
        ld r3,STACK_FRAME_PARAM(0)(sp)
        bl vsx_memcmp
        POP_BASIC_STACK(32)
        blr
FUNC_END(check_vsx)

# int preempt_vmx(vector int *varray, int *threads_starting,
#                 int *running);
# On starting will (atomically) decrement threads_starting as a signal
# that the VMX have been loaded with varray. Will proceed to check the
# validity of the VMX registers while running is not zero.
FUNC_START(preempt_vsx)
        PUSH_BASIC_STACK(512)
        std r3,STACK_FRAME_PARAM(0)(sp) # vector int *varray
        std r4,STACK_FRAME_PARAM(1)(sp) # int *threads_starting
        std r5,STACK_FRAME_PARAM(2)(sp) # int *running

        bl load_vsx
        nop

        sync
        # Atomic DEC
        ld r3,STACK_FRAME_PARAM(1)(sp)
1:      lwarx r4,0,r3
        addi r4,r4,-1
        stwcx. r4,0,r3
        bne- 1b

2:      ld r3,STACK_FRAME_PARAM(0)(sp)
        bl check_vsx
        nop
        cmpdi r3,0
        bne 3f
        ld r4,STACK_FRAME_PARAM(2)(sp)
        ld r5,0(r4)
        cmpwi r5,0
        bne 2b

3:      POP_BASIC_STACK(512)
        blr
FUNC_END(preempt_vsx)