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torvalds
GitHub Repository: torvalds/linux
 Path: blob/master/arch/alpha/include/asm/fpu.h
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/* SPDX-License-Identifier: GPL-2.0 */

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#ifndef __ASM_ALPHA_FPU_H

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#define __ASM_ALPHA_FPU_H

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#include <asm/special_insns.h>

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#include <uapi/asm/fpu.h>

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/* The following two functions don't need trapb/excb instructions

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   around the mf_fpcr/mt_fpcr instructions because (a) the kernel

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   never generates arithmetic faults and (b) call_pal instructions

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   are implied trap barriers.  */

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static inline unsigned long

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rdfpcr(void)

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{

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	unsigned long tmp, ret;

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	preempt_disable();

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	if (current_thread_info()->status & TS_SAVED_FP) {

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		ret = current_thread_info()->fp[31];

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	} else {

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#if defined(CONFIG_ALPHA_EV6) || defined(CONFIG_ALPHA_EV67)

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		__asm__ __volatile__ (

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			"ftoit $f0,%0\n\t"

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			"mf_fpcr $f0\n\t"

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			"ftoit $f0,%1\n\t"

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			"itoft %0,$f0"

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			: "=r"(tmp), "=r"(ret));

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#else

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		__asm__ __volatile__ (

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			"stt $f0,%0\n\t"

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			"mf_fpcr $f0\n\t"

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			"stt $f0,%1\n\t"

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			"ldt $f0,%0"

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			: "=m"(tmp), "=m"(ret));

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#endif

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	}

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	preempt_enable();

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	return ret;

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}

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static inline void

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wrfpcr(unsigned long val)

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{

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	unsigned long tmp;

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	preempt_disable();

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	if (current_thread_info()->status & TS_SAVED_FP) {

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		current_thread_info()->status |= TS_RESTORE_FP;

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		current_thread_info()->fp[31] = val;

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	} else {

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#if defined(CONFIG_ALPHA_EV6) || defined(CONFIG_ALPHA_EV67)

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		__asm__ __volatile__ (

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			"ftoit $f0,%0\n\t"

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			"itoft %1,$f0\n\t"

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			"mt_fpcr $f0\n\t"

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			"itoft %0,$f0"

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			: "=&r"(tmp) : "r"(val));

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#else

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		__asm__ __volatile__ (

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			"stt $f0,%0\n\t"

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			"ldt $f0,%1\n\t"

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			"mt_fpcr $f0\n\t"

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			"ldt $f0,%0"

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			: "=m"(tmp) : "m"(val));

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#endif

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	}

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	preempt_enable();

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}

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static inline unsigned long

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swcr_update_status(unsigned long swcr, unsigned long fpcr)

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{

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	/* EV6 implements most of the bits in hardware.  Collect

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	   the acrued exception bits from the real fpcr.  */

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	if (implver() == IMPLVER_EV6) {

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		swcr &= ~IEEE_STATUS_MASK;

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		swcr |= (fpcr >> 35) & IEEE_STATUS_MASK;

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	}

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	return swcr;

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}

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extern unsigned long alpha_read_fp_reg (unsigned long reg);

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extern void alpha_write_fp_reg (unsigned long reg, unsigned long val);

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extern unsigned long alpha_read_fp_reg_s (unsigned long reg);

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extern void alpha_write_fp_reg_s (unsigned long reg, unsigned long val);

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#endif /* __ASM_ALPHA_FPU_H */

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