Linux-2.6.33.2/arch/alpha/include/asm/fpu.h
#ifndef __ASM_ALPHA_FPU_H
#define __ASM_ALPHA_FPU_H
/*
* Alpha floating-point control register defines:
*/
#define FPCR_DNOD (1UL<<47) /* denorm INV trap disable */
#define FPCR_DNZ (1UL<<48) /* denorms to zero */
#define FPCR_INVD (1UL<<49) /* invalid op disable (opt.) */
#define FPCR_DZED (1UL<<50) /* division by zero disable (opt.) */
#define FPCR_OVFD (1UL<<51) /* overflow disable (optional) */
#define FPCR_INV (1UL<<52) /* invalid operation */
#define FPCR_DZE (1UL<<53) /* division by zero */
#define FPCR_OVF (1UL<<54) /* overflow */
#define FPCR_UNF (1UL<<55) /* underflow */
#define FPCR_INE (1UL<<56) /* inexact */
#define FPCR_IOV (1UL<<57) /* integer overflow */
#define FPCR_UNDZ (1UL<<60) /* underflow to zero (opt.) */
#define FPCR_UNFD (1UL<<61) /* underflow disable (opt.) */
#define FPCR_INED (1UL<<62) /* inexact disable (opt.) */
#define FPCR_SUM (1UL<<63) /* summary bit */
#define FPCR_DYN_SHIFT 58 /* first dynamic rounding mode bit */
#define FPCR_DYN_CHOPPED (0x0UL << FPCR_DYN_SHIFT) /* towards 0 */
#define FPCR_DYN_MINUS (0x1UL << FPCR_DYN_SHIFT) /* towards -INF */
#define FPCR_DYN_NORMAL (0x2UL << FPCR_DYN_SHIFT) /* towards nearest */
#define FPCR_DYN_PLUS (0x3UL << FPCR_DYN_SHIFT) /* towards +INF */
#define FPCR_DYN_MASK (0x3UL << FPCR_DYN_SHIFT)
#define FPCR_MASK 0xffff800000000000L
/*
* IEEE trap enables are implemented in software. These per-thread
* bits are stored in the "ieee_state" field of "struct thread_info".
* Thus, the bits are defined so as not to conflict with the
* floating-point enable bit (which is architected). On top of that,
* we want to make these bits compatible with OSF/1 so
* ieee_set_fp_control() etc. can be implemented easily and
* compatibly. The corresponding definitions are in
* /usr/include/machine/fpu.h under OSF/1.
*/
#define IEEE_TRAP_ENABLE_INV (1UL<<1) /* invalid op */
#define IEEE_TRAP_ENABLE_DZE (1UL<<2) /* division by zero */
#define IEEE_TRAP_ENABLE_OVF (1UL<<3) /* overflow */
#define IEEE_TRAP_ENABLE_UNF (1UL<<4) /* underflow */
#define IEEE_TRAP_ENABLE_INE (1UL<<5) /* inexact */
#define IEEE_TRAP_ENABLE_DNO (1UL<<6) /* denorm */
#define IEEE_TRAP_ENABLE_MASK (IEEE_TRAP_ENABLE_INV | IEEE_TRAP_ENABLE_DZE |\
IEEE_TRAP_ENABLE_OVF | IEEE_TRAP_ENABLE_UNF |\
IEEE_TRAP_ENABLE_INE | IEEE_TRAP_ENABLE_DNO)
/* Denorm and Underflow flushing */
#define IEEE_MAP_DMZ (1UL<<12) /* Map denorm inputs to zero */
#define IEEE_MAP_UMZ (1UL<<13) /* Map underflowed outputs to zero */
#define IEEE_MAP_MASK (IEEE_MAP_DMZ | IEEE_MAP_UMZ)
/* status bits coming from fpcr: */
#define IEEE_STATUS_INV (1UL<<17)
#define IEEE_STATUS_DZE (1UL<<18)
#define IEEE_STATUS_OVF (1UL<<19)
#define IEEE_STATUS_UNF (1UL<<20)
#define IEEE_STATUS_INE (1UL<<21)
#define IEEE_STATUS_DNO (1UL<<22)
#define IEEE_STATUS_MASK (IEEE_STATUS_INV | IEEE_STATUS_DZE | \
IEEE_STATUS_OVF | IEEE_STATUS_UNF | \
IEEE_STATUS_INE | IEEE_STATUS_DNO)
#define IEEE_SW_MASK (IEEE_TRAP_ENABLE_MASK | \
IEEE_STATUS_MASK | IEEE_MAP_MASK)
#define IEEE_CURRENT_RM_SHIFT 32
#define IEEE_CURRENT_RM_MASK (3UL<<IEEE_CURRENT_RM_SHIFT)
#define IEEE_STATUS_TO_EXCSUM_SHIFT 16
#define IEEE_INHERIT (1UL<<63) /* inherit on thread create? */
/*
* Convert the software IEEE trap enable and status bits into the
* hardware fpcr format.
*
* Digital Unix engineers receive my thanks for not defining the
* software bits identical to the hardware bits. The chip designers
* receive my thanks for making all the not-implemented fpcr bits
* RAZ forcing us to use system calls to read/write this value.
*/
static inline unsigned long
ieee_swcr_to_fpcr(unsigned long sw)
{
unsigned long fp;
fp = (sw & IEEE_STATUS_MASK) << 35;
fp |= (sw & IEEE_MAP_DMZ) << 36;
fp |= (sw & IEEE_STATUS_MASK ? FPCR_SUM : 0);
fp |= (~sw & (IEEE_TRAP_ENABLE_INV
| IEEE_TRAP_ENABLE_DZE
| IEEE_TRAP_ENABLE_OVF)) << 48;
fp |= (~sw & (IEEE_TRAP_ENABLE_UNF | IEEE_TRAP_ENABLE_INE)) << 57;
fp |= (sw & IEEE_MAP_UMZ ? FPCR_UNDZ | FPCR_UNFD : 0);
fp |= (~sw & IEEE_TRAP_ENABLE_DNO) << 41;
return fp;
}
static inline unsigned long
ieee_fpcr_to_swcr(unsigned long fp)
{
unsigned long sw;
sw = (fp >> 35) & IEEE_STATUS_MASK;
sw |= (fp >> 36) & IEEE_MAP_DMZ;
sw |= (~fp >> 48) & (IEEE_TRAP_ENABLE_INV
| IEEE_TRAP_ENABLE_DZE
| IEEE_TRAP_ENABLE_OVF);
sw |= (~fp >> 57) & (IEEE_TRAP_ENABLE_UNF | IEEE_TRAP_ENABLE_INE);
sw |= (fp >> 47) & IEEE_MAP_UMZ;
sw |= (~fp >> 41) & IEEE_TRAP_ENABLE_DNO;
return sw;
}
#ifdef __KERNEL__
/* The following two functions don't need trapb/excb instructions
around the mf_fpcr/mt_fpcr instructions because (a) the kernel
never generates arithmetic faults and (b) call_pal instructions
are implied trap barriers. */
static inline unsigned long
rdfpcr(void)
{
unsigned long tmp, ret;
#if defined(CONFIG_ALPHA_EV6) || defined(CONFIG_ALPHA_EV67)
__asm__ __volatile__ (
"ftoit $f0,%0\n\t"
"mf_fpcr $f0\n\t"
"ftoit $f0,%1\n\t"
"itoft %0,$f0"
: "=r"(tmp), "=r"(ret));
#else
__asm__ __volatile__ (
"stt $f0,%0\n\t"
"mf_fpcr $f0\n\t"
"stt $f0,%1\n\t"
"ldt $f0,%0"
: "=m"(tmp), "=m"(ret));
#endif
return ret;
}
static inline void
wrfpcr(unsigned long val)
{
unsigned long tmp;
#if defined(CONFIG_ALPHA_EV6) || defined(CONFIG_ALPHA_EV67)
__asm__ __volatile__ (
"ftoit $f0,%0\n\t"
"itoft %1,$f0\n\t"
"mt_fpcr $f0\n\t"
"itoft %0,$f0"
: "=&r"(tmp) : "r"(val));
#else
__asm__ __volatile__ (
"stt $f0,%0\n\t"
"ldt $f0,%1\n\t"
"mt_fpcr $f0\n\t"
"ldt $f0,%0"
: "=m"(tmp) : "m"(val));
#endif
}
static inline unsigned long
swcr_update_status(unsigned long swcr, unsigned long fpcr)
{
/* EV6 implements most of the bits in hardware. Collect
the acrued exception bits from the real fpcr. */
if (implver() == IMPLVER_EV6) {
swcr &= ~IEEE_STATUS_MASK;
swcr |= (fpcr >> 35) & IEEE_STATUS_MASK;
}
return swcr;
}
extern unsigned long alpha_read_fp_reg (unsigned long reg);
extern void alpha_write_fp_reg (unsigned long reg, unsigned long val);
extern unsigned long alpha_read_fp_reg_s (unsigned long reg);
extern void alpha_write_fp_reg_s (unsigned long reg, unsigned long val);
#endif /* __KERNEL__ */
#endif /* __ASM_ALPHA_FPU_H */