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v6.2
  1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * arch/sparc64/math-emu/math.c
  4 *
  5 * Copyright (C) 1997,1999 Jakub Jelinek (jj@ultra.linux.cz)
  6 * Copyright (C) 1999 David S. Miller (davem@redhat.com)
  7 *
  8 * Emulation routines originate from soft-fp package, which is part
  9 * of glibc and has appropriate copyrights in it.
 10 */
 11
 12#include <linux/types.h>
 13#include <linux/sched.h>
 14#include <linux/errno.h>
 15#include <linux/perf_event.h>
 16
 17#include <asm/fpumacro.h>
 18#include <asm/ptrace.h>
 19#include <linux/uaccess.h>
 20#include <asm/cacheflush.h>
 21
 22#include "sfp-util_64.h"
 23#include <math-emu/soft-fp.h>
 24#include <math-emu/single.h>
 25#include <math-emu/double.h>
 26#include <math-emu/quad.h>
 27
 28/* QUAD - ftt == 3 */
 29#define FMOVQ	0x003
 30#define FNEGQ	0x007
 31#define FABSQ	0x00b
 32#define FSQRTQ	0x02b
 33#define FADDQ	0x043
 34#define FSUBQ	0x047
 35#define FMULQ	0x04b
 36#define FDIVQ	0x04f
 37#define FDMULQ	0x06e
 38#define FQTOX	0x083
 39#define FXTOQ	0x08c
 40#define FQTOS	0x0c7
 41#define FQTOD	0x0cb
 42#define FITOQ	0x0cc
 43#define FSTOQ	0x0cd
 44#define FDTOQ	0x0ce
 45#define FQTOI	0x0d3
 46/* SUBNORMAL - ftt == 2 */
 47#define FSQRTS	0x029
 48#define FSQRTD	0x02a
 49#define FADDS	0x041
 50#define FADDD	0x042
 51#define FSUBS	0x045
 52#define FSUBD	0x046
 53#define FMULS	0x049
 54#define FMULD	0x04a
 55#define FDIVS	0x04d
 56#define FDIVD	0x04e
 57#define FSMULD	0x069
 58#define FSTOX	0x081
 59#define FDTOX	0x082
 60#define FDTOS	0x0c6
 61#define FSTOD	0x0c9
 62#define FSTOI	0x0d1
 63#define FDTOI	0x0d2
 64#define FXTOS	0x084 /* Only Ultra-III generates this. */
 65#define FXTOD	0x088 /* Only Ultra-III generates this. */
 66#if 0	/* Optimized inline in sparc64/kernel/entry.S */
 67#define FITOS	0x0c4 /* Only Ultra-III generates this. */
 68#endif
 69#define FITOD	0x0c8 /* Only Ultra-III generates this. */
 70/* FPOP2 */
 71#define FCMPQ	0x053
 72#define FCMPEQ	0x057
 73#define FMOVQ0	0x003
 74#define FMOVQ1	0x043
 75#define FMOVQ2	0x083
 76#define FMOVQ3	0x0c3
 77#define FMOVQI	0x103
 78#define FMOVQX	0x183
 79#define FMOVQZ	0x027
 80#define FMOVQLE	0x047
 81#define FMOVQLZ 0x067
 82#define FMOVQNZ	0x0a7
 83#define FMOVQGZ	0x0c7
 84#define FMOVQGE 0x0e7
 85
 86#define FSR_TEM_SHIFT	23UL
 87#define FSR_TEM_MASK	(0x1fUL << FSR_TEM_SHIFT)
 88#define FSR_AEXC_SHIFT	5UL
 89#define FSR_AEXC_MASK	(0x1fUL << FSR_AEXC_SHIFT)
 90#define FSR_CEXC_SHIFT	0UL
 91#define FSR_CEXC_MASK	(0x1fUL << FSR_CEXC_SHIFT)
 92
 93/* All routines returning an exception to raise should detect
 94 * such exceptions _before_ rounding to be consistent with
 95 * the behavior of the hardware in the implemented cases
 96 * (and thus with the recommendations in the V9 architecture
 97 * manual).
 98 *
 99 * We return 0 if a SIGFPE should be sent, 1 otherwise.
100 */
101static inline int record_exception(struct pt_regs *regs, int eflag)
102{
103	u64 fsr = current_thread_info()->xfsr[0];
104	int would_trap;
105
106	/* Determine if this exception would have generated a trap. */
107	would_trap = (fsr & ((long)eflag << FSR_TEM_SHIFT)) != 0UL;
108
109	/* If trapping, we only want to signal one bit. */
110	if(would_trap != 0) {
111		eflag &= ((fsr & FSR_TEM_MASK) >> FSR_TEM_SHIFT);
112		if((eflag & (eflag - 1)) != 0) {
113			if(eflag & FP_EX_INVALID)
114				eflag = FP_EX_INVALID;
115			else if(eflag & FP_EX_OVERFLOW)
116				eflag = FP_EX_OVERFLOW;
117			else if(eflag & FP_EX_UNDERFLOW)
118				eflag = FP_EX_UNDERFLOW;
119			else if(eflag & FP_EX_DIVZERO)
120				eflag = FP_EX_DIVZERO;
121			else if(eflag & FP_EX_INEXACT)
122				eflag = FP_EX_INEXACT;
123		}
124	}
125
126	/* Set CEXC, here is the rule:
127	 *
128	 *    In general all FPU ops will set one and only one
129	 *    bit in the CEXC field, this is always the case
130	 *    when the IEEE exception trap is enabled in TEM.
131	 */
132	fsr &= ~(FSR_CEXC_MASK);
133	fsr |= ((long)eflag << FSR_CEXC_SHIFT);
134
135	/* Set the AEXC field, rule is:
136	 *
137	 *    If a trap would not be generated, the
138	 *    CEXC just generated is OR'd into the
139	 *    existing value of AEXC.
140	 */
141	if(would_trap == 0)
142		fsr |= ((long)eflag << FSR_AEXC_SHIFT);
143
144	/* If trapping, indicate fault trap type IEEE. */
145	if(would_trap != 0)
146		fsr |= (1UL << 14);
147
148	current_thread_info()->xfsr[0] = fsr;
149
150	/* If we will not trap, advance the program counter over
151	 * the instruction being handled.
152	 */
153	if(would_trap == 0) {
154		regs->tpc = regs->tnpc;
155		regs->tnpc += 4;
156	}
157
158	return (would_trap ? 0 : 1);
159}
160
161typedef union {
162	u32 s;
163	u64 d;
164	u64 q[2];
165} *argp;
166
167int do_mathemu(struct pt_regs *regs, struct fpustate *f, bool illegal_insn_trap)
168{
169	unsigned long pc = regs->tpc;
170	unsigned long tstate = regs->tstate;
171	u32 insn = 0;
172	int type = 0;
173	/* ftt tells which ftt it may happen in, r is rd, b is rs2 and a is rs1. The *u arg tells
174	   whether the argument should be packed/unpacked (0 - do not unpack/pack, 1 - unpack/pack)
175	   non-u args tells the size of the argument (0 - no argument, 1 - single, 2 - double, 3 - quad */
176#define TYPE(ftt, r, ru, b, bu, a, au) type = (au << 2) | (a << 0) | (bu << 5) | (b << 3) | (ru << 8) | (r << 6) | (ftt << 9)
177	int freg;
178	static u64 zero[2] = { 0L, 0L };
179	int flags;
180	FP_DECL_EX;
181	FP_DECL_S(SA); FP_DECL_S(SB); FP_DECL_S(SR);
182	FP_DECL_D(DA); FP_DECL_D(DB); FP_DECL_D(DR);
183	FP_DECL_Q(QA); FP_DECL_Q(QB); FP_DECL_Q(QR);
184	int IR;
185	long XR, xfsr;
186
187	if (tstate & TSTATE_PRIV)
188		die_if_kernel("unfinished/unimplemented FPop from kernel", regs);
189	perf_sw_event(PERF_COUNT_SW_EMULATION_FAULTS, 1, regs, 0);
190	if (test_thread_flag(TIF_32BIT))
191		pc = (u32)pc;
192	if (get_user(insn, (u32 __user *) pc) != -EFAULT) {
193		if ((insn & 0xc1f80000) == 0x81a00000) /* FPOP1 */ {
194			switch ((insn >> 5) & 0x1ff) {
195			/* QUAD - ftt == 3 */
196			case FMOVQ:
197			case FNEGQ:
198			case FABSQ: TYPE(3,3,0,3,0,0,0); break;
199			case FSQRTQ: TYPE(3,3,1,3,1,0,0); break;
200			case FADDQ:
201			case FSUBQ:
202			case FMULQ:
203			case FDIVQ: TYPE(3,3,1,3,1,3,1); break;
204			case FDMULQ: TYPE(3,3,1,2,1,2,1); break;
205			case FQTOX: TYPE(3,2,0,3,1,0,0); break;
206			case FXTOQ: TYPE(3,3,1,2,0,0,0); break;
207			case FQTOS: TYPE(3,1,1,3,1,0,0); break;
208			case FQTOD: TYPE(3,2,1,3,1,0,0); break;
209			case FITOQ: TYPE(3,3,1,1,0,0,0); break;
210			case FSTOQ: TYPE(3,3,1,1,1,0,0); break;
211			case FDTOQ: TYPE(3,3,1,2,1,0,0); break;
212			case FQTOI: TYPE(3,1,0,3,1,0,0); break;
213
214			/* We can get either unimplemented or unfinished
215			 * for these cases.  Pre-Niagara systems generate
216			 * unfinished fpop for SUBNORMAL cases, and Niagara
217			 * always gives unimplemented fpop for fsqrt{s,d}.
218			 */
219			case FSQRTS: {
220				unsigned long x = current_thread_info()->xfsr[0];
221
222				x = (x >> 14) & 0x7;
223				TYPE(x,1,1,1,1,0,0);
224				break;
225			}
226
227			case FSQRTD: {
228				unsigned long x = current_thread_info()->xfsr[0];
229
230				x = (x >> 14) & 0x7;
231				TYPE(x,2,1,2,1,0,0);
232				break;
233			}
234
235			/* SUBNORMAL - ftt == 2 */
236			case FADDD:
237			case FSUBD:
238			case FMULD:
239			case FDIVD: TYPE(2,2,1,2,1,2,1); break;
240			case FADDS:
241			case FSUBS:
242			case FMULS:
243			case FDIVS: TYPE(2,1,1,1,1,1,1); break;
244			case FSMULD: TYPE(2,2,1,1,1,1,1); break;
245			case FSTOX: TYPE(2,2,0,1,1,0,0); break;
246			case FDTOX: TYPE(2,2,0,2,1,0,0); break;
247			case FDTOS: TYPE(2,1,1,2,1,0,0); break;
248			case FSTOD: TYPE(2,2,1,1,1,0,0); break;
249			case FSTOI: TYPE(2,1,0,1,1,0,0); break;
250			case FDTOI: TYPE(2,1,0,2,1,0,0); break;
251
252			/* Only Ultra-III generates these */
253			case FXTOS: TYPE(2,1,1,2,0,0,0); break;
254			case FXTOD: TYPE(2,2,1,2,0,0,0); break;
255#if 0			/* Optimized inline in sparc64/kernel/entry.S */
256			case FITOS: TYPE(2,1,1,1,0,0,0); break;
257#endif
258			case FITOD: TYPE(2,2,1,1,0,0,0); break;
259			}
260		}
261		else if ((insn & 0xc1f80000) == 0x81a80000) /* FPOP2 */ {
262			IR = 2;
263			switch ((insn >> 5) & 0x1ff) {
264			case FCMPQ: TYPE(3,0,0,3,1,3,1); break;
265			case FCMPEQ: TYPE(3,0,0,3,1,3,1); break;
266			/* Now the conditional fmovq support */
267			case FMOVQ0:
268			case FMOVQ1:
269			case FMOVQ2:
270			case FMOVQ3:
271				/* fmovq %fccX, %fY, %fZ */
272				if (!((insn >> 11) & 3))
273					XR = current_thread_info()->xfsr[0] >> 10;
274				else
275					XR = current_thread_info()->xfsr[0] >> (30 + ((insn >> 10) & 0x6));
276				XR &= 3;
277				IR = 0;
278				switch ((insn >> 14) & 0x7) {
279				/* case 0: IR = 0; break; */			/* Never */
280				case 1: if (XR) IR = 1; break;			/* Not Equal */
281				case 2: if (XR == 1 || XR == 2) IR = 1; break;	/* Less or Greater */
282				case 3: if (XR & 1) IR = 1; break;		/* Unordered or Less */
283				case 4: if (XR == 1) IR = 1; break;		/* Less */
284				case 5: if (XR & 2) IR = 1; break;		/* Unordered or Greater */
285				case 6: if (XR == 2) IR = 1; break;		/* Greater */
286				case 7: if (XR == 3) IR = 1; break;		/* Unordered */
287				}
288				if ((insn >> 14) & 8)
289					IR ^= 1;
290				break;
291			case FMOVQI:
292			case FMOVQX:
293				/* fmovq %[ix]cc, %fY, %fZ */
294				XR = regs->tstate >> 32;
295				if ((insn >> 5) & 0x80)
296					XR >>= 4;
297				XR &= 0xf;
298				IR = 0;
299				freg = ((XR >> 2) ^ XR) & 2;
300				switch ((insn >> 14) & 0x7) {
301				/* case 0: IR = 0; break; */			/* Never */
302				case 1: if (XR & 4) IR = 1; break;		/* Equal */
303				case 2: if ((XR & 4) || freg) IR = 1; break;	/* Less or Equal */
304				case 3: if (freg) IR = 1; break;		/* Less */
305				case 4: if (XR & 5) IR = 1; break;		/* Less or Equal Unsigned */
306				case 5: if (XR & 1) IR = 1; break;		/* Carry Set */
307				case 6: if (XR & 8) IR = 1; break;		/* Negative */
308				case 7: if (XR & 2) IR = 1; break;		/* Overflow Set */
309				}
310				if ((insn >> 14) & 8)
311					IR ^= 1;
312				break;
313			case FMOVQZ:
314			case FMOVQLE:
315			case FMOVQLZ:
316			case FMOVQNZ:
317			case FMOVQGZ:
318			case FMOVQGE:
319				freg = (insn >> 14) & 0x1f;
320				if (!freg)
321					XR = 0;
322				else if (freg < 16)
323					XR = regs->u_regs[freg];
324				else if (!test_thread_64bit_stack(regs->u_regs[UREG_FP])) {
325					struct reg_window32 __user *win32;
326					flushw_user ();
327					win32 = (struct reg_window32 __user *)((unsigned long)((u32)regs->u_regs[UREG_FP]));
328					get_user(XR, &win32->locals[freg - 16]);
329				} else {
330					struct reg_window __user *win;
331					flushw_user ();
332					win = (struct reg_window __user *)(regs->u_regs[UREG_FP] + STACK_BIAS);
333					get_user(XR, &win->locals[freg - 16]);
334				}
335				IR = 0;
336				switch ((insn >> 10) & 3) {
337				case 1: if (!XR) IR = 1; break;			/* Register Zero */
338				case 2: if (XR <= 0) IR = 1; break;		/* Register Less Than or Equal to Zero */
339				case 3: if (XR < 0) IR = 1; break;		/* Register Less Than Zero */
340				}
341				if ((insn >> 10) & 4)
342					IR ^= 1;
343				break;
344			}
345			if (IR == 0) {
346				/* The fmov test was false. Do a nop instead */
347				current_thread_info()->xfsr[0] &= ~(FSR_CEXC_MASK);
348				regs->tpc = regs->tnpc;
349				regs->tnpc += 4;
350				return 1;
351			} else if (IR == 1) {
352				/* Change the instruction into plain fmovq */
353				insn = (insn & 0x3e00001f) | 0x81a00060;
354				TYPE(3,3,0,3,0,0,0); 
355			}
356		}
357	}
358	if (type) {
359		argp rs1 = NULL, rs2 = NULL, rd = NULL;
360		
361		/* Starting with UltraSPARC-T2, the cpu does not set the FP Trap
362		 * Type field in the %fsr to unimplemented_FPop.  Nor does it
363		 * use the fp_exception_other trap.  Instead it signals an
364		 * illegal instruction and leaves the FP trap type field of
365		 * the %fsr unchanged.
366		 */
367		if (!illegal_insn_trap) {
368			int ftt = (current_thread_info()->xfsr[0] >> 14) & 0x7;
369			if (ftt != (type >> 9))
370				goto err;
371		}
372		current_thread_info()->xfsr[0] &= ~0x1c000;
373		freg = ((insn >> 14) & 0x1f);
374		switch (type & 0x3) {
375		case 3: if (freg & 2) {
376				current_thread_info()->xfsr[0] |= (6 << 14) /* invalid_fp_register */;
377				goto err;
378			}
379		case 2: freg = ((freg & 1) << 5) | (freg & 0x1e);
380		case 1: rs1 = (argp)&f->regs[freg];
381			flags = (freg < 32) ? FPRS_DL : FPRS_DU; 
382			if (!(current_thread_info()->fpsaved[0] & flags))
383				rs1 = (argp)&zero;
384			break;
385		}
386		switch (type & 0x7) {
387		case 7: FP_UNPACK_QP (QA, rs1); break;
388		case 6: FP_UNPACK_DP (DA, rs1); break;
389		case 5: FP_UNPACK_SP (SA, rs1); break;
390		}
391		freg = (insn & 0x1f);
392		switch ((type >> 3) & 0x3) {
393		case 3: if (freg & 2) {
394				current_thread_info()->xfsr[0] |= (6 << 14) /* invalid_fp_register */;
395				goto err;
396			}
397		case 2: freg = ((freg & 1) << 5) | (freg & 0x1e);
398		case 1: rs2 = (argp)&f->regs[freg];
399			flags = (freg < 32) ? FPRS_DL : FPRS_DU; 
400			if (!(current_thread_info()->fpsaved[0] & flags))
401				rs2 = (argp)&zero;
402			break;
403		}
404		switch ((type >> 3) & 0x7) {
405		case 7: FP_UNPACK_QP (QB, rs2); break;
406		case 6: FP_UNPACK_DP (DB, rs2); break;
407		case 5: FP_UNPACK_SP (SB, rs2); break;
408		}
409		freg = ((insn >> 25) & 0x1f);
410		switch ((type >> 6) & 0x3) {
411		case 3: if (freg & 2) {
412				current_thread_info()->xfsr[0] |= (6 << 14) /* invalid_fp_register */;
413				goto err;
414			}
415		case 2: freg = ((freg & 1) << 5) | (freg & 0x1e);
416		case 1: rd = (argp)&f->regs[freg];
417			flags = (freg < 32) ? FPRS_DL : FPRS_DU; 
418			if (!(current_thread_info()->fpsaved[0] & FPRS_FEF)) {
419				current_thread_info()->fpsaved[0] = FPRS_FEF;
420				current_thread_info()->gsr[0] = 0;
421			}
422			if (!(current_thread_info()->fpsaved[0] & flags)) {
423				if (freg < 32)
424					memset(f->regs, 0, 32*sizeof(u32));
425				else
426					memset(f->regs+32, 0, 32*sizeof(u32));
427			}
428			current_thread_info()->fpsaved[0] |= flags;
429			break;
430		}
431		switch ((insn >> 5) & 0x1ff) {
432		/* + */
433		case FADDS: FP_ADD_S (SR, SA, SB); break;
434		case FADDD: FP_ADD_D (DR, DA, DB); break;
435		case FADDQ: FP_ADD_Q (QR, QA, QB); break;
436		/* - */
437		case FSUBS: FP_SUB_S (SR, SA, SB); break;
438		case FSUBD: FP_SUB_D (DR, DA, DB); break;
439		case FSUBQ: FP_SUB_Q (QR, QA, QB); break;
440		/* * */
441		case FMULS: FP_MUL_S (SR, SA, SB); break;
442		case FSMULD: FP_CONV (D, S, 1, 1, DA, SA);
443			     FP_CONV (D, S, 1, 1, DB, SB);
444		case FMULD: FP_MUL_D (DR, DA, DB); break;
445		case FDMULQ: FP_CONV (Q, D, 2, 1, QA, DA);
446			     FP_CONV (Q, D, 2, 1, QB, DB);
447		case FMULQ: FP_MUL_Q (QR, QA, QB); break;
448		/* / */
449		case FDIVS: FP_DIV_S (SR, SA, SB); break;
450		case FDIVD: FP_DIV_D (DR, DA, DB); break;
451		case FDIVQ: FP_DIV_Q (QR, QA, QB); break;
452		/* sqrt */
453		case FSQRTS: FP_SQRT_S (SR, SB); break;
454		case FSQRTD: FP_SQRT_D (DR, DB); break;
455		case FSQRTQ: FP_SQRT_Q (QR, QB); break;
456		/* mov */
457		case FMOVQ: rd->q[0] = rs2->q[0]; rd->q[1] = rs2->q[1]; break;
458		case FABSQ: rd->q[0] = rs2->q[0] & 0x7fffffffffffffffUL; rd->q[1] = rs2->q[1]; break;
459		case FNEGQ: rd->q[0] = rs2->q[0] ^ 0x8000000000000000UL; rd->q[1] = rs2->q[1]; break;
460		/* float to int */
461		case FSTOI: FP_TO_INT_S (IR, SB, 32, 1); break;
462		case FDTOI: FP_TO_INT_D (IR, DB, 32, 1); break;
463		case FQTOI: FP_TO_INT_Q (IR, QB, 32, 1); break;
464		case FSTOX: FP_TO_INT_S (XR, SB, 64, 1); break;
465		case FDTOX: FP_TO_INT_D (XR, DB, 64, 1); break;
466		case FQTOX: FP_TO_INT_Q (XR, QB, 64, 1); break;
467		/* int to float */
468		case FITOQ: IR = rs2->s; FP_FROM_INT_Q (QR, IR, 32, int); break;
469		case FXTOQ: XR = rs2->d; FP_FROM_INT_Q (QR, XR, 64, long); break;
470		/* Only Ultra-III generates these */
471		case FXTOS: XR = rs2->d; FP_FROM_INT_S (SR, XR, 64, long); break;
472		case FXTOD: XR = rs2->d; FP_FROM_INT_D (DR, XR, 64, long); break;
473#if 0		/* Optimized inline in sparc64/kernel/entry.S */
474		case FITOS: IR = rs2->s; FP_FROM_INT_S (SR, IR, 32, int); break;
475#endif
476		case FITOD: IR = rs2->s; FP_FROM_INT_D (DR, IR, 32, int); break;
477		/* float to float */
478		case FSTOD: FP_CONV (D, S, 1, 1, DR, SB); break;
479		case FSTOQ: FP_CONV (Q, S, 2, 1, QR, SB); break;
480		case FDTOQ: FP_CONV (Q, D, 2, 1, QR, DB); break;
481		case FDTOS: FP_CONV (S, D, 1, 1, SR, DB); break;
482		case FQTOS: FP_CONV (S, Q, 1, 2, SR, QB); break;
483		case FQTOD: FP_CONV (D, Q, 1, 2, DR, QB); break;
484		/* comparison */
485		case FCMPQ:
486		case FCMPEQ:
487			FP_CMP_Q(XR, QB, QA, 3);
488			if (XR == 3 &&
489			    (((insn >> 5) & 0x1ff) == FCMPEQ ||
490			     FP_ISSIGNAN_Q(QA) ||
491			     FP_ISSIGNAN_Q(QB)))
492				FP_SET_EXCEPTION (FP_EX_INVALID);
493		}
494		if (!FP_INHIBIT_RESULTS) {
495			switch ((type >> 6) & 0x7) {
496			case 0: xfsr = current_thread_info()->xfsr[0];
497				if (XR == -1) XR = 2;
498				switch (freg & 3) {
499				/* fcc0, 1, 2, 3 */
500				case 0: xfsr &= ~0xc00; xfsr |= (XR << 10); break;
501				case 1: xfsr &= ~0x300000000UL; xfsr |= (XR << 32); break;
502				case 2: xfsr &= ~0xc00000000UL; xfsr |= (XR << 34); break;
503				case 3: xfsr &= ~0x3000000000UL; xfsr |= (XR << 36); break;
504				}
505				current_thread_info()->xfsr[0] = xfsr;
506				break;
507			case 1: rd->s = IR; break;
508			case 2: rd->d = XR; break;
509			case 5: FP_PACK_SP (rd, SR); break;
510			case 6: FP_PACK_DP (rd, DR); break;
511			case 7: FP_PACK_QP (rd, QR); break;
512			}
513		}
514
515		if(_fex != 0)
516			return record_exception(regs, _fex);
517
518		/* Success and no exceptions detected. */
519		current_thread_info()->xfsr[0] &= ~(FSR_CEXC_MASK);
520		regs->tpc = regs->tnpc;
521		regs->tnpc += 4;
522		return 1;
523	}
524err:	return 0;
525}
v3.15
 
  1/*
  2 * arch/sparc64/math-emu/math.c
  3 *
  4 * Copyright (C) 1997,1999 Jakub Jelinek (jj@ultra.linux.cz)
  5 * Copyright (C) 1999 David S. Miller (davem@redhat.com)
  6 *
  7 * Emulation routines originate from soft-fp package, which is part
  8 * of glibc and has appropriate copyrights in it.
  9 */
 10
 11#include <linux/types.h>
 12#include <linux/sched.h>
 13#include <linux/errno.h>
 14#include <linux/perf_event.h>
 15
 16#include <asm/fpumacro.h>
 17#include <asm/ptrace.h>
 18#include <asm/uaccess.h>
 19#include <asm/cacheflush.h>
 20
 21#include "sfp-util_64.h"
 22#include <math-emu/soft-fp.h>
 23#include <math-emu/single.h>
 24#include <math-emu/double.h>
 25#include <math-emu/quad.h>
 26
 27/* QUAD - ftt == 3 */
 28#define FMOVQ	0x003
 29#define FNEGQ	0x007
 30#define FABSQ	0x00b
 31#define FSQRTQ	0x02b
 32#define FADDQ	0x043
 33#define FSUBQ	0x047
 34#define FMULQ	0x04b
 35#define FDIVQ	0x04f
 36#define FDMULQ	0x06e
 37#define FQTOX	0x083
 38#define FXTOQ	0x08c
 39#define FQTOS	0x0c7
 40#define FQTOD	0x0cb
 41#define FITOQ	0x0cc
 42#define FSTOQ	0x0cd
 43#define FDTOQ	0x0ce
 44#define FQTOI	0x0d3
 45/* SUBNORMAL - ftt == 2 */
 46#define FSQRTS	0x029
 47#define FSQRTD	0x02a
 48#define FADDS	0x041
 49#define FADDD	0x042
 50#define FSUBS	0x045
 51#define FSUBD	0x046
 52#define FMULS	0x049
 53#define FMULD	0x04a
 54#define FDIVS	0x04d
 55#define FDIVD	0x04e
 56#define FSMULD	0x069
 57#define FSTOX	0x081
 58#define FDTOX	0x082
 59#define FDTOS	0x0c6
 60#define FSTOD	0x0c9
 61#define FSTOI	0x0d1
 62#define FDTOI	0x0d2
 63#define FXTOS	0x084 /* Only Ultra-III generates this. */
 64#define FXTOD	0x088 /* Only Ultra-III generates this. */
 65#if 0	/* Optimized inline in sparc64/kernel/entry.S */
 66#define FITOS	0x0c4 /* Only Ultra-III generates this. */
 67#endif
 68#define FITOD	0x0c8 /* Only Ultra-III generates this. */
 69/* FPOP2 */
 70#define FCMPQ	0x053
 71#define FCMPEQ	0x057
 72#define FMOVQ0	0x003
 73#define FMOVQ1	0x043
 74#define FMOVQ2	0x083
 75#define FMOVQ3	0x0c3
 76#define FMOVQI	0x103
 77#define FMOVQX	0x183
 78#define FMOVQZ	0x027
 79#define FMOVQLE	0x047
 80#define FMOVQLZ 0x067
 81#define FMOVQNZ	0x0a7
 82#define FMOVQGZ	0x0c7
 83#define FMOVQGE 0x0e7
 84
 85#define FSR_TEM_SHIFT	23UL
 86#define FSR_TEM_MASK	(0x1fUL << FSR_TEM_SHIFT)
 87#define FSR_AEXC_SHIFT	5UL
 88#define FSR_AEXC_MASK	(0x1fUL << FSR_AEXC_SHIFT)
 89#define FSR_CEXC_SHIFT	0UL
 90#define FSR_CEXC_MASK	(0x1fUL << FSR_CEXC_SHIFT)
 91
 92/* All routines returning an exception to raise should detect
 93 * such exceptions _before_ rounding to be consistent with
 94 * the behavior of the hardware in the implemented cases
 95 * (and thus with the recommendations in the V9 architecture
 96 * manual).
 97 *
 98 * We return 0 if a SIGFPE should be sent, 1 otherwise.
 99 */
100static inline int record_exception(struct pt_regs *regs, int eflag)
101{
102	u64 fsr = current_thread_info()->xfsr[0];
103	int would_trap;
104
105	/* Determine if this exception would have generated a trap. */
106	would_trap = (fsr & ((long)eflag << FSR_TEM_SHIFT)) != 0UL;
107
108	/* If trapping, we only want to signal one bit. */
109	if(would_trap != 0) {
110		eflag &= ((fsr & FSR_TEM_MASK) >> FSR_TEM_SHIFT);
111		if((eflag & (eflag - 1)) != 0) {
112			if(eflag & FP_EX_INVALID)
113				eflag = FP_EX_INVALID;
114			else if(eflag & FP_EX_OVERFLOW)
115				eflag = FP_EX_OVERFLOW;
116			else if(eflag & FP_EX_UNDERFLOW)
117				eflag = FP_EX_UNDERFLOW;
118			else if(eflag & FP_EX_DIVZERO)
119				eflag = FP_EX_DIVZERO;
120			else if(eflag & FP_EX_INEXACT)
121				eflag = FP_EX_INEXACT;
122		}
123	}
124
125	/* Set CEXC, here is the rule:
126	 *
127	 *    In general all FPU ops will set one and only one
128	 *    bit in the CEXC field, this is always the case
129	 *    when the IEEE exception trap is enabled in TEM.
130	 */
131	fsr &= ~(FSR_CEXC_MASK);
132	fsr |= ((long)eflag << FSR_CEXC_SHIFT);
133
134	/* Set the AEXC field, rule is:
135	 *
136	 *    If a trap would not be generated, the
137	 *    CEXC just generated is OR'd into the
138	 *    existing value of AEXC.
139	 */
140	if(would_trap == 0)
141		fsr |= ((long)eflag << FSR_AEXC_SHIFT);
142
143	/* If trapping, indicate fault trap type IEEE. */
144	if(would_trap != 0)
145		fsr |= (1UL << 14);
146
147	current_thread_info()->xfsr[0] = fsr;
148
149	/* If we will not trap, advance the program counter over
150	 * the instruction being handled.
151	 */
152	if(would_trap == 0) {
153		regs->tpc = regs->tnpc;
154		regs->tnpc += 4;
155	}
156
157	return (would_trap ? 0 : 1);
158}
159
160typedef union {
161	u32 s;
162	u64 d;
163	u64 q[2];
164} *argp;
165
166int do_mathemu(struct pt_regs *regs, struct fpustate *f, bool illegal_insn_trap)
167{
168	unsigned long pc = regs->tpc;
169	unsigned long tstate = regs->tstate;
170	u32 insn = 0;
171	int type = 0;
172	/* ftt tells which ftt it may happen in, r is rd, b is rs2 and a is rs1. The *u arg tells
173	   whether the argument should be packed/unpacked (0 - do not unpack/pack, 1 - unpack/pack)
174	   non-u args tells the size of the argument (0 - no argument, 1 - single, 2 - double, 3 - quad */
175#define TYPE(ftt, r, ru, b, bu, a, au) type = (au << 2) | (a << 0) | (bu << 5) | (b << 3) | (ru << 8) | (r << 6) | (ftt << 9)
176	int freg;
177	static u64 zero[2] = { 0L, 0L };
178	int flags;
179	FP_DECL_EX;
180	FP_DECL_S(SA); FP_DECL_S(SB); FP_DECL_S(SR);
181	FP_DECL_D(DA); FP_DECL_D(DB); FP_DECL_D(DR);
182	FP_DECL_Q(QA); FP_DECL_Q(QB); FP_DECL_Q(QR);
183	int IR;
184	long XR, xfsr;
185
186	if (tstate & TSTATE_PRIV)
187		die_if_kernel("unfinished/unimplemented FPop from kernel", regs);
188	perf_sw_event(PERF_COUNT_SW_EMULATION_FAULTS, 1, regs, 0);
189	if (test_thread_flag(TIF_32BIT))
190		pc = (u32)pc;
191	if (get_user(insn, (u32 __user *) pc) != -EFAULT) {
192		if ((insn & 0xc1f80000) == 0x81a00000) /* FPOP1 */ {
193			switch ((insn >> 5) & 0x1ff) {
194			/* QUAD - ftt == 3 */
195			case FMOVQ:
196			case FNEGQ:
197			case FABSQ: TYPE(3,3,0,3,0,0,0); break;
198			case FSQRTQ: TYPE(3,3,1,3,1,0,0); break;
199			case FADDQ:
200			case FSUBQ:
201			case FMULQ:
202			case FDIVQ: TYPE(3,3,1,3,1,3,1); break;
203			case FDMULQ: TYPE(3,3,1,2,1,2,1); break;
204			case FQTOX: TYPE(3,2,0,3,1,0,0); break;
205			case FXTOQ: TYPE(3,3,1,2,0,0,0); break;
206			case FQTOS: TYPE(3,1,1,3,1,0,0); break;
207			case FQTOD: TYPE(3,2,1,3,1,0,0); break;
208			case FITOQ: TYPE(3,3,1,1,0,0,0); break;
209			case FSTOQ: TYPE(3,3,1,1,1,0,0); break;
210			case FDTOQ: TYPE(3,3,1,2,1,0,0); break;
211			case FQTOI: TYPE(3,1,0,3,1,0,0); break;
212
213			/* We can get either unimplemented or unfinished
214			 * for these cases.  Pre-Niagara systems generate
215			 * unfinished fpop for SUBNORMAL cases, and Niagara
216			 * always gives unimplemented fpop for fsqrt{s,d}.
217			 */
218			case FSQRTS: {
219				unsigned long x = current_thread_info()->xfsr[0];
220
221				x = (x >> 14) & 0x7;
222				TYPE(x,1,1,1,1,0,0);
223				break;
224			}
225
226			case FSQRTD: {
227				unsigned long x = current_thread_info()->xfsr[0];
228
229				x = (x >> 14) & 0x7;
230				TYPE(x,2,1,2,1,0,0);
231				break;
232			}
233
234			/* SUBNORMAL - ftt == 2 */
235			case FADDD:
236			case FSUBD:
237			case FMULD:
238			case FDIVD: TYPE(2,2,1,2,1,2,1); break;
239			case FADDS:
240			case FSUBS:
241			case FMULS:
242			case FDIVS: TYPE(2,1,1,1,1,1,1); break;
243			case FSMULD: TYPE(2,2,1,1,1,1,1); break;
244			case FSTOX: TYPE(2,2,0,1,1,0,0); break;
245			case FDTOX: TYPE(2,2,0,2,1,0,0); break;
246			case FDTOS: TYPE(2,1,1,2,1,0,0); break;
247			case FSTOD: TYPE(2,2,1,1,1,0,0); break;
248			case FSTOI: TYPE(2,1,0,1,1,0,0); break;
249			case FDTOI: TYPE(2,1,0,2,1,0,0); break;
250
251			/* Only Ultra-III generates these */
252			case FXTOS: TYPE(2,1,1,2,0,0,0); break;
253			case FXTOD: TYPE(2,2,1,2,0,0,0); break;
254#if 0			/* Optimized inline in sparc64/kernel/entry.S */
255			case FITOS: TYPE(2,1,1,1,0,0,0); break;
256#endif
257			case FITOD: TYPE(2,2,1,1,0,0,0); break;
258			}
259		}
260		else if ((insn & 0xc1f80000) == 0x81a80000) /* FPOP2 */ {
261			IR = 2;
262			switch ((insn >> 5) & 0x1ff) {
263			case FCMPQ: TYPE(3,0,0,3,1,3,1); break;
264			case FCMPEQ: TYPE(3,0,0,3,1,3,1); break;
265			/* Now the conditional fmovq support */
266			case FMOVQ0:
267			case FMOVQ1:
268			case FMOVQ2:
269			case FMOVQ3:
270				/* fmovq %fccX, %fY, %fZ */
271				if (!((insn >> 11) & 3))
272					XR = current_thread_info()->xfsr[0] >> 10;
273				else
274					XR = current_thread_info()->xfsr[0] >> (30 + ((insn >> 10) & 0x6));
275				XR &= 3;
276				IR = 0;
277				switch ((insn >> 14) & 0x7) {
278				/* case 0: IR = 0; break; */			/* Never */
279				case 1: if (XR) IR = 1; break;			/* Not Equal */
280				case 2: if (XR == 1 || XR == 2) IR = 1; break;	/* Less or Greater */
281				case 3: if (XR & 1) IR = 1; break;		/* Unordered or Less */
282				case 4: if (XR == 1) IR = 1; break;		/* Less */
283				case 5: if (XR & 2) IR = 1; break;		/* Unordered or Greater */
284				case 6: if (XR == 2) IR = 1; break;		/* Greater */
285				case 7: if (XR == 3) IR = 1; break;		/* Unordered */
286				}
287				if ((insn >> 14) & 8)
288					IR ^= 1;
289				break;
290			case FMOVQI:
291			case FMOVQX:
292				/* fmovq %[ix]cc, %fY, %fZ */
293				XR = regs->tstate >> 32;
294				if ((insn >> 5) & 0x80)
295					XR >>= 4;
296				XR &= 0xf;
297				IR = 0;
298				freg = ((XR >> 2) ^ XR) & 2;
299				switch ((insn >> 14) & 0x7) {
300				/* case 0: IR = 0; break; */			/* Never */
301				case 1: if (XR & 4) IR = 1; break;		/* Equal */
302				case 2: if ((XR & 4) || freg) IR = 1; break;	/* Less or Equal */
303				case 3: if (freg) IR = 1; break;		/* Less */
304				case 4: if (XR & 5) IR = 1; break;		/* Less or Equal Unsigned */
305				case 5: if (XR & 1) IR = 1; break;		/* Carry Set */
306				case 6: if (XR & 8) IR = 1; break;		/* Negative */
307				case 7: if (XR & 2) IR = 1; break;		/* Overflow Set */
308				}
309				if ((insn >> 14) & 8)
310					IR ^= 1;
311				break;
312			case FMOVQZ:
313			case FMOVQLE:
314			case FMOVQLZ:
315			case FMOVQNZ:
316			case FMOVQGZ:
317			case FMOVQGE:
318				freg = (insn >> 14) & 0x1f;
319				if (!freg)
320					XR = 0;
321				else if (freg < 16)
322					XR = regs->u_regs[freg];
323				else if (!test_thread_64bit_stack(regs->u_regs[UREG_FP])) {
324					struct reg_window32 __user *win32;
325					flushw_user ();
326					win32 = (struct reg_window32 __user *)((unsigned long)((u32)regs->u_regs[UREG_FP]));
327					get_user(XR, &win32->locals[freg - 16]);
328				} else {
329					struct reg_window __user *win;
330					flushw_user ();
331					win = (struct reg_window __user *)(regs->u_regs[UREG_FP] + STACK_BIAS);
332					get_user(XR, &win->locals[freg - 16]);
333				}
334				IR = 0;
335				switch ((insn >> 10) & 3) {
336				case 1: if (!XR) IR = 1; break;			/* Register Zero */
337				case 2: if (XR <= 0) IR = 1; break;		/* Register Less Than or Equal to Zero */
338				case 3: if (XR < 0) IR = 1; break;		/* Register Less Than Zero */
339				}
340				if ((insn >> 10) & 4)
341					IR ^= 1;
342				break;
343			}
344			if (IR == 0) {
345				/* The fmov test was false. Do a nop instead */
346				current_thread_info()->xfsr[0] &= ~(FSR_CEXC_MASK);
347				regs->tpc = regs->tnpc;
348				regs->tnpc += 4;
349				return 1;
350			} else if (IR == 1) {
351				/* Change the instruction into plain fmovq */
352				insn = (insn & 0x3e00001f) | 0x81a00060;
353				TYPE(3,3,0,3,0,0,0); 
354			}
355		}
356	}
357	if (type) {
358		argp rs1 = NULL, rs2 = NULL, rd = NULL;
359		
360		/* Starting with UltraSPARC-T2, the cpu does not set the FP Trap
361		 * Type field in the %fsr to unimplemented_FPop.  Nor does it
362		 * use the fp_exception_other trap.  Instead it signals an
363		 * illegal instruction and leaves the FP trap type field of
364		 * the %fsr unchanged.
365		 */
366		if (!illegal_insn_trap) {
367			int ftt = (current_thread_info()->xfsr[0] >> 14) & 0x7;
368			if (ftt != (type >> 9))
369				goto err;
370		}
371		current_thread_info()->xfsr[0] &= ~0x1c000;
372		freg = ((insn >> 14) & 0x1f);
373		switch (type & 0x3) {
374		case 3: if (freg & 2) {
375				current_thread_info()->xfsr[0] |= (6 << 14) /* invalid_fp_register */;
376				goto err;
377			}
378		case 2: freg = ((freg & 1) << 5) | (freg & 0x1e);
379		case 1: rs1 = (argp)&f->regs[freg];
380			flags = (freg < 32) ? FPRS_DL : FPRS_DU; 
381			if (!(current_thread_info()->fpsaved[0] & flags))
382				rs1 = (argp)&zero;
383			break;
384		}
385		switch (type & 0x7) {
386		case 7: FP_UNPACK_QP (QA, rs1); break;
387		case 6: FP_UNPACK_DP (DA, rs1); break;
388		case 5: FP_UNPACK_SP (SA, rs1); break;
389		}
390		freg = (insn & 0x1f);
391		switch ((type >> 3) & 0x3) {
392		case 3: if (freg & 2) {
393				current_thread_info()->xfsr[0] |= (6 << 14) /* invalid_fp_register */;
394				goto err;
395			}
396		case 2: freg = ((freg & 1) << 5) | (freg & 0x1e);
397		case 1: rs2 = (argp)&f->regs[freg];
398			flags = (freg < 32) ? FPRS_DL : FPRS_DU; 
399			if (!(current_thread_info()->fpsaved[0] & flags))
400				rs2 = (argp)&zero;
401			break;
402		}
403		switch ((type >> 3) & 0x7) {
404		case 7: FP_UNPACK_QP (QB, rs2); break;
405		case 6: FP_UNPACK_DP (DB, rs2); break;
406		case 5: FP_UNPACK_SP (SB, rs2); break;
407		}
408		freg = ((insn >> 25) & 0x1f);
409		switch ((type >> 6) & 0x3) {
410		case 3: if (freg & 2) {
411				current_thread_info()->xfsr[0] |= (6 << 14) /* invalid_fp_register */;
412				goto err;
413			}
414		case 2: freg = ((freg & 1) << 5) | (freg & 0x1e);
415		case 1: rd = (argp)&f->regs[freg];
416			flags = (freg < 32) ? FPRS_DL : FPRS_DU; 
417			if (!(current_thread_info()->fpsaved[0] & FPRS_FEF)) {
418				current_thread_info()->fpsaved[0] = FPRS_FEF;
419				current_thread_info()->gsr[0] = 0;
420			}
421			if (!(current_thread_info()->fpsaved[0] & flags)) {
422				if (freg < 32)
423					memset(f->regs, 0, 32*sizeof(u32));
424				else
425					memset(f->regs+32, 0, 32*sizeof(u32));
426			}
427			current_thread_info()->fpsaved[0] |= flags;
428			break;
429		}
430		switch ((insn >> 5) & 0x1ff) {
431		/* + */
432		case FADDS: FP_ADD_S (SR, SA, SB); break;
433		case FADDD: FP_ADD_D (DR, DA, DB); break;
434		case FADDQ: FP_ADD_Q (QR, QA, QB); break;
435		/* - */
436		case FSUBS: FP_SUB_S (SR, SA, SB); break;
437		case FSUBD: FP_SUB_D (DR, DA, DB); break;
438		case FSUBQ: FP_SUB_Q (QR, QA, QB); break;
439		/* * */
440		case FMULS: FP_MUL_S (SR, SA, SB); break;
441		case FSMULD: FP_CONV (D, S, 1, 1, DA, SA);
442			     FP_CONV (D, S, 1, 1, DB, SB);
443		case FMULD: FP_MUL_D (DR, DA, DB); break;
444		case FDMULQ: FP_CONV (Q, D, 2, 1, QA, DA);
445			     FP_CONV (Q, D, 2, 1, QB, DB);
446		case FMULQ: FP_MUL_Q (QR, QA, QB); break;
447		/* / */
448		case FDIVS: FP_DIV_S (SR, SA, SB); break;
449		case FDIVD: FP_DIV_D (DR, DA, DB); break;
450		case FDIVQ: FP_DIV_Q (QR, QA, QB); break;
451		/* sqrt */
452		case FSQRTS: FP_SQRT_S (SR, SB); break;
453		case FSQRTD: FP_SQRT_D (DR, DB); break;
454		case FSQRTQ: FP_SQRT_Q (QR, QB); break;
455		/* mov */
456		case FMOVQ: rd->q[0] = rs2->q[0]; rd->q[1] = rs2->q[1]; break;
457		case FABSQ: rd->q[0] = rs2->q[0] & 0x7fffffffffffffffUL; rd->q[1] = rs2->q[1]; break;
458		case FNEGQ: rd->q[0] = rs2->q[0] ^ 0x8000000000000000UL; rd->q[1] = rs2->q[1]; break;
459		/* float to int */
460		case FSTOI: FP_TO_INT_S (IR, SB, 32, 1); break;
461		case FDTOI: FP_TO_INT_D (IR, DB, 32, 1); break;
462		case FQTOI: FP_TO_INT_Q (IR, QB, 32, 1); break;
463		case FSTOX: FP_TO_INT_S (XR, SB, 64, 1); break;
464		case FDTOX: FP_TO_INT_D (XR, DB, 64, 1); break;
465		case FQTOX: FP_TO_INT_Q (XR, QB, 64, 1); break;
466		/* int to float */
467		case FITOQ: IR = rs2->s; FP_FROM_INT_Q (QR, IR, 32, int); break;
468		case FXTOQ: XR = rs2->d; FP_FROM_INT_Q (QR, XR, 64, long); break;
469		/* Only Ultra-III generates these */
470		case FXTOS: XR = rs2->d; FP_FROM_INT_S (SR, XR, 64, long); break;
471		case FXTOD: XR = rs2->d; FP_FROM_INT_D (DR, XR, 64, long); break;
472#if 0		/* Optimized inline in sparc64/kernel/entry.S */
473		case FITOS: IR = rs2->s; FP_FROM_INT_S (SR, IR, 32, int); break;
474#endif
475		case FITOD: IR = rs2->s; FP_FROM_INT_D (DR, IR, 32, int); break;
476		/* float to float */
477		case FSTOD: FP_CONV (D, S, 1, 1, DR, SB); break;
478		case FSTOQ: FP_CONV (Q, S, 2, 1, QR, SB); break;
479		case FDTOQ: FP_CONV (Q, D, 2, 1, QR, DB); break;
480		case FDTOS: FP_CONV (S, D, 1, 1, SR, DB); break;
481		case FQTOS: FP_CONV (S, Q, 1, 2, SR, QB); break;
482		case FQTOD: FP_CONV (D, Q, 1, 2, DR, QB); break;
483		/* comparison */
484		case FCMPQ:
485		case FCMPEQ:
486			FP_CMP_Q(XR, QB, QA, 3);
487			if (XR == 3 &&
488			    (((insn >> 5) & 0x1ff) == FCMPEQ ||
489			     FP_ISSIGNAN_Q(QA) ||
490			     FP_ISSIGNAN_Q(QB)))
491				FP_SET_EXCEPTION (FP_EX_INVALID);
492		}
493		if (!FP_INHIBIT_RESULTS) {
494			switch ((type >> 6) & 0x7) {
495			case 0: xfsr = current_thread_info()->xfsr[0];
496				if (XR == -1) XR = 2;
497				switch (freg & 3) {
498				/* fcc0, 1, 2, 3 */
499				case 0: xfsr &= ~0xc00; xfsr |= (XR << 10); break;
500				case 1: xfsr &= ~0x300000000UL; xfsr |= (XR << 32); break;
501				case 2: xfsr &= ~0xc00000000UL; xfsr |= (XR << 34); break;
502				case 3: xfsr &= ~0x3000000000UL; xfsr |= (XR << 36); break;
503				}
504				current_thread_info()->xfsr[0] = xfsr;
505				break;
506			case 1: rd->s = IR; break;
507			case 2: rd->d = XR; break;
508			case 5: FP_PACK_SP (rd, SR); break;
509			case 6: FP_PACK_DP (rd, DR); break;
510			case 7: FP_PACK_QP (rd, QR); break;
511			}
512		}
513
514		if(_fex != 0)
515			return record_exception(regs, _fex);
516
517		/* Success and no exceptions detected. */
518		current_thread_info()->xfsr[0] &= ~(FSR_CEXC_MASK);
519		regs->tpc = regs->tnpc;
520		regs->tnpc += 4;
521		return 1;
522	}
523err:	return 0;
524}