powerpc/math/fpu_asm.S

0001 /* SPDX-License-Identifier: GPL-2.0-or-later */
0002 /*
0003  * Copyright 2015, Cyril Bur, IBM Corp.
0004  */
0005
0006 #include "basic_asm.h"
0007 #include "fpu_asm.h"
0008
0009 FUNC_START(check_fpu)
0010     mr r4,r3
0011     li  r3,1 # assume a bad result
0012     lfd f0,0(r4)
0013     fcmpu   cr1,f0,f14
0014     bne cr1,1f
0015     lfd f0,8(r4)
0016     fcmpu   cr1,f0,f15
0017     bne cr1,1f
0018     lfd f0,16(r4)
0019     fcmpu   cr1,f0,f16
0020     bne cr1,1f
0021     lfd f0,24(r4)
0022     fcmpu   cr1,f0,f17
0023     bne cr1,1f
0024     lfd f0,32(r4)
0025     fcmpu   cr1,f0,f18
0026     bne cr1,1f
0027     lfd f0,40(r4)
0028     fcmpu   cr1,f0,f19
0029     bne cr1,1f
0030     lfd f0,48(r4)
0031     fcmpu   cr1,f0,f20
0032     bne cr1,1f
0033     lfd f0,56(r4)
0034     fcmpu   cr1,f0,f21
0035     bne cr1,1f
0036     lfd f0,64(r4)
0037     fcmpu   cr1,f0,f22
0038     bne cr1,1f
0039     lfd f0,72(r4)
0040     fcmpu   cr1,f0,f23
0041     bne cr1,1f
0042     lfd f0,80(r4)
0043     fcmpu   cr1,f0,f24
0044     bne cr1,1f
0045     lfd f0,88(r4)
0046     fcmpu   cr1,f0,f25
0047     bne cr1,1f
0048     lfd f0,96(r4)
0049     fcmpu   cr1,f0,f26
0050     bne cr1,1f
0051     lfd f0,104(r4)
0052     fcmpu   cr1,f0,f27
0053     bne cr1,1f
0054     lfd f0,112(r4)
0055     fcmpu   cr1,f0,f28
0056     bne cr1,1f
0057     lfd f0,120(r4)
0058     fcmpu   cr1,f0,f29
0059     bne cr1,1f
0060     lfd f0,128(r4)
0061     fcmpu   cr1,f0,f30
0062     bne cr1,1f
0063     lfd f0,136(r4)
0064     fcmpu   cr1,f0,f31
0065     bne cr1,1f
0066     li  r3,0 # Success!!!
0067 1:  blr
0068
0069 FUNC_START(test_fpu)
0070     # r3 holds pointer to where to put the result of fork
0071     # r4 holds pointer to the pid
0072     # f14-f31 are non volatiles
0073     PUSH_BASIC_STACK(256)
0074     PUSH_FPU(256)
0075     std r3,STACK_FRAME_PARAM(0)(sp) # Address of darray
0076     std r4,STACK_FRAME_PARAM(1)(sp) # Address of pid
0077
0078     bl load_fpu
0079     nop
0080     li  r0,__NR_fork
0081     sc
0082
0083     # pass the result of the fork to the caller
0084     ld  r9,STACK_FRAME_PARAM(1)(sp)
0085     std r3,0(r9)
0086
0087     ld r3,STACK_FRAME_PARAM(0)(sp)
0088     bl check_fpu
0089     nop
0090
0091     POP_FPU(256)
0092     POP_BASIC_STACK(256)
0093     blr
0094 FUNC_END(test_fpu)
0095
0096 # int preempt_fpu(double *darray, int *threads_running, int *running)
0097 # On starting will (atomically) decrement not_ready as a signal that the FPU
0098 # has been loaded with darray. Will proceed to check the validity of the FPU
0099 # registers while running is not zero.
0100 FUNC_START(preempt_fpu)
0101     PUSH_BASIC_STACK(256)
0102     PUSH_FPU(256)
0103     std r3,STACK_FRAME_PARAM(0)(sp) # double *darray
0104     std r4,STACK_FRAME_PARAM(1)(sp) # int *threads_starting
0105     std r5,STACK_FRAME_PARAM(2)(sp) # int *running
0106
0107     bl load_fpu
0108     nop
0109
0110     sync
0111     # Atomic DEC
0112     ld r3,STACK_FRAME_PARAM(1)(sp)
0113 1:  lwarx r4,0,r3
0114     addi r4,r4,-1
0115     stwcx. r4,0,r3
0116     bne- 1b
0117
0118 2:  ld r3,STACK_FRAME_PARAM(0)(sp)
0119     bl check_fpu
0120     nop
0121     cmpdi r3,0
0122     bne 3f
0123     ld r4,STACK_FRAME_PARAM(2)(sp)
0124     ld r5,0(r4)
0125     cmpwi r5,0
0126     bne 2b
0127
0128 3:  POP_FPU(256)
0129     POP_BASIC_STACK(256)
0130     blr
0131 FUNC_END(preempt_fpu)