NetBSD/sys/arch/m68k/fpe/fpu_arith.h
briggs 59422960ea PR 7220 from Ken Nakata:
I've fixed most (not all) m68k FPE bugs that give bogus
calculation results, esp. fsqrt instruction.  Also, the internal FP
representation has been reduced from 115-bit mantissa to 67-bit
mantissa which reduced the required mantissa operation roughly by one
fourth.  I've done an extensive (though not exhaustive - it's
impossible!) test on the internal routines by feeding them randomly
generated FP numbers, and found that the new code is more precise than
MC68040 FPU (it seems to have a rounding bug).

[ Only change was to keep fpu_calcea.c's name instead of renaming to
  fpu_ea.c in Ken's patch.  --akb ]
1999-05-30 20:17:48 +00:00

175 lines
6.3 KiB
C

/* $NetBSD: fpu_arith.h,v 1.2 1999/05/30 20:17:48 briggs Exp $ */
/*
* Copyright (c) 1992, 1993
* The Regents of the University of California. All rights reserved.
*
* This software was developed by the Computer Systems Engineering group
* at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
* contributed to Berkeley.
*
* All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Lawrence Berkeley Laboratory.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)fpu_arith.h 8.1 (Berkeley) 6/11/93
*/
/*
* Extended-precision arithmetic.
*
* We hold the notion of a `carry register', which may or may not be a
* machine carry bit or register. On the SPARC, it is just the machine's
* carry bit.
*
* In the worst case, you can compute the carry from x+y as
* (unsigned)(x + y) < (unsigned)x
* and from x+y+c as
* ((unsigned)(x + y + c) <= (unsigned)x && (y|c) != 0)
* for example.
*/
#ifndef FPE_USE_ASM
/* set up for extended-precision arithemtic */
#define FPU_DECL_CARRY quad_t fpu_carry, fpu_tmp;
/*
* We have three kinds of add:
* add with carry: r = x + y + c
* add (ignoring current carry) and set carry: c'r = x + y + 0
* add with carry and set carry: c'r = x + y + c
* The macros use `C' for `use carry' and `S' for `set carry'.
* Note that the state of the carry is undefined after ADDC and SUBC,
* so if all you have for these is `add with carry and set carry',
* that is OK.
*
* The same goes for subtract, except that we compute x - y - c.
*
* Finally, we have a way to get the carry into a `regular' variable,
* or set it from a value. SET_CARRY turns 0 into no-carry, nonzero
* into carry; GET_CARRY sets its argument to 0 or 1.
*/
#define FPU_ADDC(r, x, y) \
(r) = (x) + (y) + (!!fpu_carry)
#define FPU_ADDS(r, x, y) \
{ \
fpu_tmp = (quad_t)(x) + (quad_t)(y); \
(r) = (u_int)fpu_tmp; \
fpu_carry = ((fpu_tmp & 0xffffffff00000000LL) != 0); \
}
#define FPU_ADDCS(r, x, y) \
{ \
fpu_tmp = (quad_t)(x) + (quad_t)(y) + (!!fpu_carry); \
(r) = (u_int)fpu_tmp; \
fpu_carry = ((fpu_tmp & 0xffffffff00000000LL) != 0); \
}
#define FPU_SUBC(r, x, y) \
(r) = (x) - (y) - (!!fpu_carry)
#define FPU_SUBS(r, x, y) \
{ \
fpu_tmp = (quad_t)(x) - (quad_t)(y); \
(r) = (u_int)fpu_tmp; \
fpu_carry = ((fpu_tmp & 0xffffffff00000000LL) != 0); \
}
#define FPU_SUBCS(r, x, y) \
{ \
fpu_tmp = (quad_t)(x) - (quad_t)(y) - (!!fpu_carry); \
(r) = (u_int)fpu_tmp; \
fpu_carry = ((fpu_tmp & 0xffffffff00000000LL) != 0); \
}
#define FPU_GET_CARRY(r) (r) = (!!fpu_carry)
#define FPU_SET_CARRY(v) fpu_carry = ((v) != 0)
#else
/* set up for extended-precision arithemtic */
#define FPU_DECL_CARRY register int fpu_tmp;
/*
* We have three kinds of add:
* add with carry: r = x + y + c
* add (ignoring current carry) and set carry: c'r = x + y + 0
* add with carry and set carry: c'r = x + y + c
* The macros use `C' for `use carry' and `S' for `set carry'.
* Note that the state of the carry is undefined after ADDC and SUBC,
* so if all you have for these is `add with carry and set carry',
* that is OK.
*
* The same goes for subtract, except that we compute x - y - c.
*
* Finally, we have a way to get the carry into a `regular' variable,
* or set it from a value. SET_CARRY turns 0 into no-carry, nonzero
* into carry; GET_CARRY sets its argument to 0 or 1.
*/
#define FPU_ADDC(r, x, y) \
{ \
asm volatile("movel %1,%0" : "=d"(fpu_tmp) : "g"(x)); \
asm volatile("addxl %1,%0" : "=d"(fpu_tmp) : "d"(y)); \
asm volatile("movel %1,%0" : "=g"(r) : "r"(fpu_tmp)); \
}
#define FPU_ADDS(r, x, y) \
{ \
asm volatile("movel %1,%0" : "=d"(fpu_tmp) : "g"(x)); \
asm volatile("addl %1,%0" : "=d"(fpu_tmp) : "g"(y)); \
asm volatile("movel %1,%0" : "=g"(r) : "r"(fpu_tmp)); \
}
#define FPU_ADDCS(r, x, y) FPU_ADDC(r, x, y)
#define FPU_SUBC(r, x, y) \
{ \
asm volatile("movel %1,%0" : "=d"(fpu_tmp) : "g"(x)); \
asm volatile("subxl %1,%0" : "=d"(fpu_tmp) : "d"(y)); \
asm volatile("movel %1,%0" : "=g"(r) : "r"(fpu_tmp)); \
}
#define FPU_SUBS(r, x, y) \
{ \
asm volatile("movel %1,%0" : "=d"(fpu_tmp) : "g"(x)); \
asm volatile("subl %1,%0" : "=d"(fpu_tmp) : "g"(y)); \
asm volatile("movel %1,%0" : "=g"(r) : "r"(fpu_tmp)); \
}
#define FPU_SUBCS(r, x, y) FPU_SUBC(r, x, y)
#define FPU_GET_CARRY(r) \
{ \
asm volatile("moveq #0,%0" : "=d"(r)); \
asm volatile("addxl %0,%0" : "+d"(r)); \
}
#define FPU_SET_CARRY(v) \
{ \
asm volatile("moveq #0,%0" : "=d"(fpu_tmp)); \
asm volatile("subl %1,%0" : "=d"(fpu_tmp) : "g"(v)); \
}
#endif /* FPE_USE_ASM */