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1/* SPDX-License-Identifier: GPL-2.0 */
2#include <asm/processor.h>
3#include <asm/ppc_asm.h>
4#include <asm/reg.h>
5#include <asm/asm-offsets.h>
6#include <asm/cputable.h>
7#include <asm/thread_info.h>
8#include <asm/page.h>
9#include <asm/ptrace.h>
10#include <asm/export.h>
11#include <asm/asm-compat.h>
12
13/*
14 * Load state from memory into VMX registers including VSCR.
15 * Assumes the caller has enabled VMX in the MSR.
16 */
17_GLOBAL(load_vr_state)
18 li r4,VRSTATE_VSCR
19 lvx v0,r4,r3
20 mtvscr v0
21 REST_32VRS(0,r4,r3)
22 blr
23EXPORT_SYMBOL(load_vr_state)
24_ASM_NOKPROBE_SYMBOL(load_vr_state); /* used by restore_math */
25
26/*
27 * Store VMX state into memory, including VSCR.
28 * Assumes the caller has enabled VMX in the MSR.
29 */
30_GLOBAL(store_vr_state)
31 SAVE_32VRS(0, r4, r3)
32 mfvscr v0
33 li r4, VRSTATE_VSCR
34 stvx v0, r4, r3
35 blr
36EXPORT_SYMBOL(store_vr_state)
37
38/*
39 * Disable VMX for the task which had it previously,
40 * and save its vector registers in its thread_struct.
41 * Enables the VMX for use in the kernel on return.
42 * On SMP we know the VMX is free, since we give it up every
43 * switch (ie, no lazy save of the vector registers).
44 *
45 * Note that on 32-bit this can only use registers that will be
46 * restored by fast_exception_return, i.e. r3 - r6, r10 and r11.
47 */
48_GLOBAL(load_up_altivec)
49 mfmsr r5 /* grab the current MSR */
50 oris r5,r5,MSR_VEC@h
51 MTMSRD(r5) /* enable use of AltiVec now */
52 isync
53
54 /*
55 * While userspace in general ignores VRSAVE, glibc uses it as a boolean
56 * to optimise userspace context save/restore. Whenever we take an
57 * altivec unavailable exception we must set VRSAVE to something non
58 * zero. Set it to all 1s. See also the programming note in the ISA.
59 */
60 mfspr r4,SPRN_VRSAVE
61 cmpwi 0,r4,0
62 bne+ 1f
63 li r4,-1
64 mtspr SPRN_VRSAVE,r4
651:
66 /* enable use of VMX after return */
67#ifdef CONFIG_PPC32
68 mfspr r5,SPRN_SPRG_THREAD /* current task's THREAD (phys) */
69 oris r9,r9,MSR_VEC@h
70#ifdef CONFIG_VMAP_STACK
71 tovirt(r5, r5)
72#endif
73#else
74 ld r4,PACACURRENT(r13)
75 addi r5,r4,THREAD /* Get THREAD */
76 oris r12,r12,MSR_VEC@h
77 std r12,_MSR(r1)
78#endif
79 li r4,1
80 stb r4,THREAD_LOAD_VEC(r5)
81 addi r6,r5,THREAD_VRSTATE
82 li r4,1
83 li r10,VRSTATE_VSCR
84 stw r4,THREAD_USED_VR(r5)
85 lvx v0,r10,r6
86 mtvscr v0
87 REST_32VRS(0,r4,r6)
88 /* restore registers and return */
89 blr
90_ASM_NOKPROBE_SYMBOL(load_up_altivec)
91
92/*
93 * save_altivec(tsk)
94 * Save the vector registers to its thread_struct
95 */
96_GLOBAL(save_altivec)
97 addi r3,r3,THREAD /* want THREAD of task */
98 PPC_LL r7,THREAD_VRSAVEAREA(r3)
99 PPC_LL r5,PT_REGS(r3)
100 PPC_LCMPI 0,r7,0
101 bne 2f
102 addi r7,r3,THREAD_VRSTATE
1032: SAVE_32VRS(0,r4,r7)
104 mfvscr v0
105 li r4,VRSTATE_VSCR
106 stvx v0,r4,r7
107 blr
108
109#ifdef CONFIG_VSX
110
111#ifdef CONFIG_PPC32
112#error This asm code isn't ready for 32-bit kernels
113#endif
114
115/*
116 * load_up_vsx(unused, unused, tsk)
117 * Disable VSX for the task which had it previously,
118 * and save its vector registers in its thread_struct.
119 * Reuse the fp and vsx saves, but first check to see if they have
120 * been saved already.
121 */
122_GLOBAL(load_up_vsx)
123/* Load FP and VSX registers if they haven't been done yet */
124 andi. r5,r12,MSR_FP
125 beql+ load_up_fpu /* skip if already loaded */
126 andis. r5,r12,MSR_VEC@h
127 beql+ load_up_altivec /* skip if already loaded */
128
129 ld r4,PACACURRENT(r13)
130 addi r4,r4,THREAD /* Get THREAD */
131 li r6,1
132 stw r6,THREAD_USED_VSR(r4) /* ... also set thread used vsr */
133 /* enable use of VSX after return */
134 oris r12,r12,MSR_VSX@h
135 std r12,_MSR(r1)
136 b fast_interrupt_return
137
138#endif /* CONFIG_VSX */
139
140
141/*
142 * The routines below are in assembler so we can closely control the
143 * usage of floating-point registers. These routines must be called
144 * with preempt disabled.
145 */
146#ifdef CONFIG_PPC32
147 .data
148fpzero:
149 .long 0
150fpone:
151 .long 0x3f800000 /* 1.0 in single-precision FP */
152fphalf:
153 .long 0x3f000000 /* 0.5 in single-precision FP */
154
155#define LDCONST(fr, name) \
156 lis r11,name@ha; \
157 lfs fr,name@l(r11)
158#else
159
160 .section ".toc","aw"
161fpzero:
162 .tc FD_0_0[TC],0
163fpone:
164 .tc FD_3ff00000_0[TC],0x3ff0000000000000 /* 1.0 */
165fphalf:
166 .tc FD_3fe00000_0[TC],0x3fe0000000000000 /* 0.5 */
167
168#define LDCONST(fr, name) \
169 lfd fr,name@toc(r2)
170#endif
171
172 .text
173/*
174 * Internal routine to enable floating point and set FPSCR to 0.
175 * Don't call it from C; it doesn't use the normal calling convention.
176 */
177fpenable:
178#ifdef CONFIG_PPC32
179 stwu r1,-64(r1)
180#else
181 stdu r1,-64(r1)
182#endif
183 mfmsr r10
184 ori r11,r10,MSR_FP
185 mtmsr r11
186 isync
187 stfd fr0,24(r1)
188 stfd fr1,16(r1)
189 stfd fr31,8(r1)
190 LDCONST(fr1, fpzero)
191 mffs fr31
192 MTFSF_L(fr1)
193 blr
194
195fpdisable:
196 mtlr r12
197 MTFSF_L(fr31)
198 lfd fr31,8(r1)
199 lfd fr1,16(r1)
200 lfd fr0,24(r1)
201 mtmsr r10
202 isync
203 addi r1,r1,64
204 blr
205
206/*
207 * Vector add, floating point.
208 */
209_GLOBAL(vaddfp)
210 mflr r12
211 bl fpenable
212 li r0,4
213 mtctr r0
214 li r6,0
2151: lfsx fr0,r4,r6
216 lfsx fr1,r5,r6
217 fadds fr0,fr0,fr1
218 stfsx fr0,r3,r6
219 addi r6,r6,4
220 bdnz 1b
221 b fpdisable
222
223/*
224 * Vector subtract, floating point.
225 */
226_GLOBAL(vsubfp)
227 mflr r12
228 bl fpenable
229 li r0,4
230 mtctr r0
231 li r6,0
2321: lfsx fr0,r4,r6
233 lfsx fr1,r5,r6
234 fsubs fr0,fr0,fr1
235 stfsx fr0,r3,r6
236 addi r6,r6,4
237 bdnz 1b
238 b fpdisable
239
240/*
241 * Vector multiply and add, floating point.
242 */
243_GLOBAL(vmaddfp)
244 mflr r12
245 bl fpenable
246 stfd fr2,32(r1)
247 li r0,4
248 mtctr r0
249 li r7,0
2501: lfsx fr0,r4,r7
251 lfsx fr1,r5,r7
252 lfsx fr2,r6,r7
253 fmadds fr0,fr0,fr2,fr1
254 stfsx fr0,r3,r7
255 addi r7,r7,4
256 bdnz 1b
257 lfd fr2,32(r1)
258 b fpdisable
259
260/*
261 * Vector negative multiply and subtract, floating point.
262 */
263_GLOBAL(vnmsubfp)
264 mflr r12
265 bl fpenable
266 stfd fr2,32(r1)
267 li r0,4
268 mtctr r0
269 li r7,0
2701: lfsx fr0,r4,r7
271 lfsx fr1,r5,r7
272 lfsx fr2,r6,r7
273 fnmsubs fr0,fr0,fr2,fr1
274 stfsx fr0,r3,r7
275 addi r7,r7,4
276 bdnz 1b
277 lfd fr2,32(r1)
278 b fpdisable
279
280/*
281 * Vector reciprocal estimate. We just compute 1.0/x.
282 * r3 -> destination, r4 -> source.
283 */
284_GLOBAL(vrefp)
285 mflr r12
286 bl fpenable
287 li r0,4
288 LDCONST(fr1, fpone)
289 mtctr r0
290 li r6,0
2911: lfsx fr0,r4,r6
292 fdivs fr0,fr1,fr0
293 stfsx fr0,r3,r6
294 addi r6,r6,4
295 bdnz 1b
296 b fpdisable
297
298/*
299 * Vector reciprocal square-root estimate, floating point.
300 * We use the frsqrte instruction for the initial estimate followed
301 * by 2 iterations of Newton-Raphson to get sufficient accuracy.
302 * r3 -> destination, r4 -> source.
303 */
304_GLOBAL(vrsqrtefp)
305 mflr r12
306 bl fpenable
307 stfd fr2,32(r1)
308 stfd fr3,40(r1)
309 stfd fr4,48(r1)
310 stfd fr5,56(r1)
311 li r0,4
312 LDCONST(fr4, fpone)
313 LDCONST(fr5, fphalf)
314 mtctr r0
315 li r6,0
3161: lfsx fr0,r4,r6
317 frsqrte fr1,fr0 /* r = frsqrte(s) */
318 fmuls fr3,fr1,fr0 /* r * s */
319 fmuls fr2,fr1,fr5 /* r * 0.5 */
320 fnmsubs fr3,fr1,fr3,fr4 /* 1 - s * r * r */
321 fmadds fr1,fr2,fr3,fr1 /* r = r + 0.5 * r * (1 - s * r * r) */
322 fmuls fr3,fr1,fr0 /* r * s */
323 fmuls fr2,fr1,fr5 /* r * 0.5 */
324 fnmsubs fr3,fr1,fr3,fr4 /* 1 - s * r * r */
325 fmadds fr1,fr2,fr3,fr1 /* r = r + 0.5 * r * (1 - s * r * r) */
326 stfsx fr1,r3,r6
327 addi r6,r6,4
328 bdnz 1b
329 lfd fr5,56(r1)
330 lfd fr4,48(r1)
331 lfd fr3,40(r1)
332 lfd fr2,32(r1)
333 b fpdisable
1#include <asm/processor.h>
2#include <asm/ppc_asm.h>
3#include <asm/reg.h>
4#include <asm/asm-offsets.h>
5#include <asm/cputable.h>
6#include <asm/thread_info.h>
7#include <asm/page.h>
8#include <asm/ptrace.h>
9
10/*
11 * load_up_altivec(unused, unused, tsk)
12 * Disable VMX for the task which had it previously,
13 * and save its vector registers in its thread_struct.
14 * Enables the VMX for use in the kernel on return.
15 * On SMP we know the VMX is free, since we give it up every
16 * switch (ie, no lazy save of the vector registers).
17 */
18_GLOBAL(load_up_altivec)
19 mfmsr r5 /* grab the current MSR */
20 oris r5,r5,MSR_VEC@h
21 MTMSRD(r5) /* enable use of AltiVec now */
22 isync
23
24/*
25 * For SMP, we don't do lazy VMX switching because it just gets too
26 * horrendously complex, especially when a task switches from one CPU
27 * to another. Instead we call giveup_altvec in switch_to.
28 * VRSAVE isn't dealt with here, that is done in the normal context
29 * switch code. Note that we could rely on vrsave value to eventually
30 * avoid saving all of the VREGs here...
31 */
32#ifndef CONFIG_SMP
33 LOAD_REG_ADDRBASE(r3, last_task_used_altivec)
34 toreal(r3)
35 PPC_LL r4,ADDROFF(last_task_used_altivec)(r3)
36 PPC_LCMPI 0,r4,0
37 beq 1f
38
39 /* Save VMX state to last_task_used_altivec's THREAD struct */
40 toreal(r4)
41 addi r4,r4,THREAD
42 SAVE_32VRS(0,r5,r4)
43 mfvscr vr0
44 li r10,THREAD_VSCR
45 stvx vr0,r10,r4
46 /* Disable VMX for last_task_used_altivec */
47 PPC_LL r5,PT_REGS(r4)
48 toreal(r5)
49 PPC_LL r4,_MSR-STACK_FRAME_OVERHEAD(r5)
50 lis r10,MSR_VEC@h
51 andc r4,r4,r10
52 PPC_STL r4,_MSR-STACK_FRAME_OVERHEAD(r5)
531:
54#endif /* CONFIG_SMP */
55
56 /* Hack: if we get an altivec unavailable trap with VRSAVE
57 * set to all zeros, we assume this is a broken application
58 * that fails to set it properly, and thus we switch it to
59 * all 1's
60 */
61 mfspr r4,SPRN_VRSAVE
62 cmpwi 0,r4,0
63 bne+ 1f
64 li r4,-1
65 mtspr SPRN_VRSAVE,r4
661:
67 /* enable use of VMX after return */
68#ifdef CONFIG_PPC32
69 mfspr r5,SPRN_SPRG_THREAD /* current task's THREAD (phys) */
70 oris r9,r9,MSR_VEC@h
71#else
72 ld r4,PACACURRENT(r13)
73 addi r5,r4,THREAD /* Get THREAD */
74 oris r12,r12,MSR_VEC@h
75 std r12,_MSR(r1)
76#endif
77 li r4,1
78 li r10,THREAD_VSCR
79 stw r4,THREAD_USED_VR(r5)
80 lvx vr0,r10,r5
81 mtvscr vr0
82 REST_32VRS(0,r4,r5)
83#ifndef CONFIG_SMP
84 /* Update last_task_used_altivec to 'current' */
85 subi r4,r5,THREAD /* Back to 'current' */
86 fromreal(r4)
87 PPC_STL r4,ADDROFF(last_task_used_altivec)(r3)
88#endif /* CONFIG_SMP */
89 /* restore registers and return */
90 blr
91
92_GLOBAL(giveup_altivec_notask)
93 mfmsr r3
94 andis. r4,r3,MSR_VEC@h
95 bnelr /* Already enabled? */
96 oris r3,r3,MSR_VEC@h
97 SYNC
98 MTMSRD(r3) /* enable use of VMX now */
99 isync
100 blr
101
102/*
103 * giveup_altivec(tsk)
104 * Disable VMX for the task given as the argument,
105 * and save the vector registers in its thread_struct.
106 * Enables the VMX for use in the kernel on return.
107 */
108_GLOBAL(giveup_altivec)
109 mfmsr r5
110 oris r5,r5,MSR_VEC@h
111 SYNC
112 MTMSRD(r5) /* enable use of VMX now */
113 isync
114 PPC_LCMPI 0,r3,0
115 beqlr /* if no previous owner, done */
116 addi r3,r3,THREAD /* want THREAD of task */
117 PPC_LL r5,PT_REGS(r3)
118 PPC_LCMPI 0,r5,0
119 SAVE_32VRS(0,r4,r3)
120 mfvscr vr0
121 li r4,THREAD_VSCR
122 stvx vr0,r4,r3
123 beq 1f
124 PPC_LL r4,_MSR-STACK_FRAME_OVERHEAD(r5)
125#ifdef CONFIG_VSX
126BEGIN_FTR_SECTION
127 lis r3,(MSR_VEC|MSR_VSX)@h
128FTR_SECTION_ELSE
129 lis r3,MSR_VEC@h
130ALT_FTR_SECTION_END_IFSET(CPU_FTR_VSX)
131#else
132 lis r3,MSR_VEC@h
133#endif
134 andc r4,r4,r3 /* disable FP for previous task */
135 PPC_STL r4,_MSR-STACK_FRAME_OVERHEAD(r5)
1361:
137#ifndef CONFIG_SMP
138 li r5,0
139 LOAD_REG_ADDRBASE(r4,last_task_used_altivec)
140 PPC_STL r5,ADDROFF(last_task_used_altivec)(r4)
141#endif /* CONFIG_SMP */
142 blr
143
144#ifdef CONFIG_VSX
145
146#ifdef CONFIG_PPC32
147#error This asm code isn't ready for 32-bit kernels
148#endif
149
150/*
151 * load_up_vsx(unused, unused, tsk)
152 * Disable VSX for the task which had it previously,
153 * and save its vector registers in its thread_struct.
154 * Reuse the fp and vsx saves, but first check to see if they have
155 * been saved already.
156 */
157_GLOBAL(load_up_vsx)
158/* Load FP and VSX registers if they haven't been done yet */
159 andi. r5,r12,MSR_FP
160 beql+ load_up_fpu /* skip if already loaded */
161 andis. r5,r12,MSR_VEC@h
162 beql+ load_up_altivec /* skip if already loaded */
163
164#ifndef CONFIG_SMP
165 ld r3,last_task_used_vsx@got(r2)
166 ld r4,0(r3)
167 cmpdi 0,r4,0
168 beq 1f
169 /* Disable VSX for last_task_used_vsx */
170 addi r4,r4,THREAD
171 ld r5,PT_REGS(r4)
172 ld r4,_MSR-STACK_FRAME_OVERHEAD(r5)
173 lis r6,MSR_VSX@h
174 andc r6,r4,r6
175 std r6,_MSR-STACK_FRAME_OVERHEAD(r5)
1761:
177#endif /* CONFIG_SMP */
178 ld r4,PACACURRENT(r13)
179 addi r4,r4,THREAD /* Get THREAD */
180 li r6,1
181 stw r6,THREAD_USED_VSR(r4) /* ... also set thread used vsr */
182 /* enable use of VSX after return */
183 oris r12,r12,MSR_VSX@h
184 std r12,_MSR(r1)
185#ifndef CONFIG_SMP
186 /* Update last_task_used_vsx to 'current' */
187 ld r4,PACACURRENT(r13)
188 std r4,0(r3)
189#endif /* CONFIG_SMP */
190 b fast_exception_return
191
192/*
193 * __giveup_vsx(tsk)
194 * Disable VSX for the task given as the argument.
195 * Does NOT save vsx registers.
196 * Enables the VSX for use in the kernel on return.
197 */
198_GLOBAL(__giveup_vsx)
199 mfmsr r5
200 oris r5,r5,MSR_VSX@h
201 mtmsrd r5 /* enable use of VSX now */
202 isync
203
204 cmpdi 0,r3,0
205 beqlr- /* if no previous owner, done */
206 addi r3,r3,THREAD /* want THREAD of task */
207 ld r5,PT_REGS(r3)
208 cmpdi 0,r5,0
209 beq 1f
210 ld r4,_MSR-STACK_FRAME_OVERHEAD(r5)
211 lis r3,MSR_VSX@h
212 andc r4,r4,r3 /* disable VSX for previous task */
213 std r4,_MSR-STACK_FRAME_OVERHEAD(r5)
2141:
215#ifndef CONFIG_SMP
216 li r5,0
217 ld r4,last_task_used_vsx@got(r2)
218 std r5,0(r4)
219#endif /* CONFIG_SMP */
220 blr
221
222#endif /* CONFIG_VSX */
223
224
225/*
226 * The routines below are in assembler so we can closely control the
227 * usage of floating-point registers. These routines must be called
228 * with preempt disabled.
229 */
230#ifdef CONFIG_PPC32
231 .data
232fpzero:
233 .long 0
234fpone:
235 .long 0x3f800000 /* 1.0 in single-precision FP */
236fphalf:
237 .long 0x3f000000 /* 0.5 in single-precision FP */
238
239#define LDCONST(fr, name) \
240 lis r11,name@ha; \
241 lfs fr,name@l(r11)
242#else
243
244 .section ".toc","aw"
245fpzero:
246 .tc FD_0_0[TC],0
247fpone:
248 .tc FD_3ff00000_0[TC],0x3ff0000000000000 /* 1.0 */
249fphalf:
250 .tc FD_3fe00000_0[TC],0x3fe0000000000000 /* 0.5 */
251
252#define LDCONST(fr, name) \
253 lfd fr,name@toc(r2)
254#endif
255
256 .text
257/*
258 * Internal routine to enable floating point and set FPSCR to 0.
259 * Don't call it from C; it doesn't use the normal calling convention.
260 */
261fpenable:
262#ifdef CONFIG_PPC32
263 stwu r1,-64(r1)
264#else
265 stdu r1,-64(r1)
266#endif
267 mfmsr r10
268 ori r11,r10,MSR_FP
269 mtmsr r11
270 isync
271 stfd fr0,24(r1)
272 stfd fr1,16(r1)
273 stfd fr31,8(r1)
274 LDCONST(fr1, fpzero)
275 mffs fr31
276 MTFSF_L(fr1)
277 blr
278
279fpdisable:
280 mtlr r12
281 MTFSF_L(fr31)
282 lfd fr31,8(r1)
283 lfd fr1,16(r1)
284 lfd fr0,24(r1)
285 mtmsr r10
286 isync
287 addi r1,r1,64
288 blr
289
290/*
291 * Vector add, floating point.
292 */
293_GLOBAL(vaddfp)
294 mflr r12
295 bl fpenable
296 li r0,4
297 mtctr r0
298 li r6,0
2991: lfsx fr0,r4,r6
300 lfsx fr1,r5,r6
301 fadds fr0,fr0,fr1
302 stfsx fr0,r3,r6
303 addi r6,r6,4
304 bdnz 1b
305 b fpdisable
306
307/*
308 * Vector subtract, floating point.
309 */
310_GLOBAL(vsubfp)
311 mflr r12
312 bl fpenable
313 li r0,4
314 mtctr r0
315 li r6,0
3161: lfsx fr0,r4,r6
317 lfsx fr1,r5,r6
318 fsubs fr0,fr0,fr1
319 stfsx fr0,r3,r6
320 addi r6,r6,4
321 bdnz 1b
322 b fpdisable
323
324/*
325 * Vector multiply and add, floating point.
326 */
327_GLOBAL(vmaddfp)
328 mflr r12
329 bl fpenable
330 stfd fr2,32(r1)
331 li r0,4
332 mtctr r0
333 li r7,0
3341: lfsx fr0,r4,r7
335 lfsx fr1,r5,r7
336 lfsx fr2,r6,r7
337 fmadds fr0,fr0,fr2,fr1
338 stfsx fr0,r3,r7
339 addi r7,r7,4
340 bdnz 1b
341 lfd fr2,32(r1)
342 b fpdisable
343
344/*
345 * Vector negative multiply and subtract, floating point.
346 */
347_GLOBAL(vnmsubfp)
348 mflr r12
349 bl fpenable
350 stfd fr2,32(r1)
351 li r0,4
352 mtctr r0
353 li r7,0
3541: lfsx fr0,r4,r7
355 lfsx fr1,r5,r7
356 lfsx fr2,r6,r7
357 fnmsubs fr0,fr0,fr2,fr1
358 stfsx fr0,r3,r7
359 addi r7,r7,4
360 bdnz 1b
361 lfd fr2,32(r1)
362 b fpdisable
363
364/*
365 * Vector reciprocal estimate. We just compute 1.0/x.
366 * r3 -> destination, r4 -> source.
367 */
368_GLOBAL(vrefp)
369 mflr r12
370 bl fpenable
371 li r0,4
372 LDCONST(fr1, fpone)
373 mtctr r0
374 li r6,0
3751: lfsx fr0,r4,r6
376 fdivs fr0,fr1,fr0
377 stfsx fr0,r3,r6
378 addi r6,r6,4
379 bdnz 1b
380 b fpdisable
381
382/*
383 * Vector reciprocal square-root estimate, floating point.
384 * We use the frsqrte instruction for the initial estimate followed
385 * by 2 iterations of Newton-Raphson to get sufficient accuracy.
386 * r3 -> destination, r4 -> source.
387 */
388_GLOBAL(vrsqrtefp)
389 mflr r12
390 bl fpenable
391 stfd fr2,32(r1)
392 stfd fr3,40(r1)
393 stfd fr4,48(r1)
394 stfd fr5,56(r1)
395 li r0,4
396 LDCONST(fr4, fpone)
397 LDCONST(fr5, fphalf)
398 mtctr r0
399 li r6,0
4001: lfsx fr0,r4,r6
401 frsqrte fr1,fr0 /* r = frsqrte(s) */
402 fmuls fr3,fr1,fr0 /* r * s */
403 fmuls fr2,fr1,fr5 /* r * 0.5 */
404 fnmsubs fr3,fr1,fr3,fr4 /* 1 - s * r * r */
405 fmadds fr1,fr2,fr3,fr1 /* r = r + 0.5 * r * (1 - s * r * r) */
406 fmuls fr3,fr1,fr0 /* r * s */
407 fmuls fr2,fr1,fr5 /* r * 0.5 */
408 fnmsubs fr3,fr1,fr3,fr4 /* 1 - s * r * r */
409 fmadds fr1,fr2,fr3,fr1 /* r = r + 0.5 * r * (1 - s * r * r) */
410 stfsx fr1,r3,r6
411 addi r6,r6,4
412 bdnz 1b
413 lfd fr5,56(r1)
414 lfd fr4,48(r1)
415 lfd fr3,40(r1)
416 lfd fr2,32(r1)
417 b fpdisable