![[BACK]](/icons/back.gif){kind=icon}
Return to sint.sa CVS log ![[TXT]](/icons/text.gif){kind=icon}
![[DIR]](/icons/dir.gif){kind=icon}
Up to [local] / sys / arch / m68k / fpsp|
Return to sint.sa CVS log | Up to [local] / sys / arch / m68k / fpsp |
1.1 nbrk 1: * $OpenBSD: sint.sa,v 1.2 1996/05/29 21:05:38 niklas Exp $
2: * $NetBSD: sint.sa,v 1.2 1994/10/26 07:49:48 cgd Exp $
3:
4: * MOTOROLA MICROPROCESSOR & MEMORY TECHNOLOGY GROUP
5: * M68000 Hi-Performance Microprocessor Division
6: * M68040 Software Package
7: *
8: * M68040 Software Package Copyright (c) 1993, 1994 Motorola Inc.
9: * All rights reserved.
10: *
11: * THE SOFTWARE is provided on an "AS IS" basis and without warranty.
12: * To the maximum extent permitted by applicable law,
13: * MOTOROLA DISCLAIMS ALL WARRANTIES WHETHER EXPRESS OR IMPLIED,
14: * INCLUDING IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A
15: * PARTICULAR PURPOSE and any warranty against infringement with
16: * regard to the SOFTWARE (INCLUDING ANY MODIFIED VERSIONS THEREOF)
17: * and any accompanying written materials.
18: *
19: * To the maximum extent permitted by applicable law,
20: * IN NO EVENT SHALL MOTOROLA BE LIABLE FOR ANY DAMAGES WHATSOEVER
21: * (INCLUDING WITHOUT LIMITATION, DAMAGES FOR LOSS OF BUSINESS
22: * PROFITS, BUSINESS INTERRUPTION, LOSS OF BUSINESS INFORMATION, OR
23: * OTHER PECUNIARY LOSS) ARISING OF THE USE OR INABILITY TO USE THE
24: * SOFTWARE. Motorola assumes no responsibility for the maintenance
25: * and support of the SOFTWARE.
26: *
27: * You are hereby granted a copyright license to use, modify, and
28: * distribute the SOFTWARE so long as this entire notice is retained
29: * without alteration in any modified and/or redistributed versions,
30: * and that such modified versions are clearly identified as such.
31: * No licenses are granted by implication, estoppel or otherwise
32: * under any patents or trademarks of Motorola, Inc.
33:
34: *
35: * sint.sa 3.1 12/10/90
36: *
37: * The entry point sINT computes the rounded integer
38: * equivalent of the input argument, sINTRZ computes
39: * the integer rounded to zero of the input argument.
40: *
41: * Entry points sint and sintrz are called from do_func
42: * to emulate the fint and fintrz unimplemented instructions,
43: * respectively. Entry point sintdo is used by bindec.
44: *
45: * Input: (Entry points sint and sintrz) Double-extended
46: * number X in the ETEMP space in the floating-point
47: * save stack.
48: * (Entry point sintdo) Double-extended number X in
49: * location pointed to by the address register a0.
50: * (Entry point sintd) Double-extended denormalized
51: * number X in the ETEMP space in the floating-point
52: * save stack.
53: *
54: * Output: The function returns int(X) or intrz(X) in fp0.
55: *
56: * Modifies: fp0.
57: *
58: * Algorithm: (sint and sintrz)
59: *
60: * 1. If exp(X) >= 63, return X.
61: * If exp(X) < 0, return +/- 0 or +/- 1, according to
62: * the rounding mode.
63: *
64: * 2. (X is in range) set rsc = 63 - exp(X). Unnormalize the
65: * result to the exponent $403e.
66: *
67: * 3. Round the result in the mode given in USER_FPCR. For
68: * sintrz, force round-to-zero mode.
69: *
70: * 4. Normalize the rounded result; store in fp0.
71: *
72: * For the denormalized cases, force the correct result
73: * for the given sign and rounding mode.
74: *
75: * Sign(X)
76: * RMODE + -
77: * ----- --------
78: * RN +0 -0
79: * RZ +0 -0
80: * RM +0 -1
81: * RP +1 -0
82: *
83:
84: SINT IDNT 2,1 Motorola 040 Floating Point Software Package
85:
86: section 8
87:
88: include fpsp.h
89:
90: xref dnrm_lp
91: xref nrm_set
92: xref round
93: xref t_inx2
94: xref ld_pone
95: xref ld_mone
96: xref ld_pzero
97: xref ld_mzero
98: xref snzrinx
99:
100: *
101: * FINT
102: *
103: xdef sint
104: sint:
105: bfextu FPCR_MODE(a6){2:2},d1 ;use user's mode for rounding
106: * ;implicity has extend precision
107: * ;in upper word.
108: move.l d1,L_SCR1(a6) ;save mode bits
109: bra.b sintexc
110:
111: *
112: * FINT with extended denorm inputs.
113: *
114: xdef sintd
115: sintd:
116: btst.b #5,FPCR_MODE(a6)
117: beq snzrinx ;if round nearest or round zero, +/- 0
118: btst.b #4,FPCR_MODE(a6)
119: beq.b rnd_mns
120: rnd_pls:
121: btst.b #sign_bit,LOCAL_EX(a0)
122: bne.b sintmz
123: bsr ld_pone ;if round plus inf and pos, answer is +1
124: bra t_inx2
125: rnd_mns:
126: btst.b #sign_bit,LOCAL_EX(a0)
127: beq.b sintpz
128: bsr ld_mone ;if round mns inf and neg, answer is -1
129: bra t_inx2
130: sintpz:
131: bsr ld_pzero
132: bra t_inx2
133: sintmz:
134: bsr ld_mzero
135: bra t_inx2
136:
137: *
138: * FINTRZ
139: *
140: xdef sintrz
141: sintrz:
142: move.l #1,L_SCR1(a6) ;use rz mode for rounding
143: * ;implicity has extend precision
144: * ;in upper word.
145: bra.b sintexc
146: *
147: * SINTDO
148: *
149: * Input: a0 points to an IEEE extended format operand
150: * Output: fp0 has the result
151: *
152: * Exeptions:
153: *
154: * If the subroutine results in an inexact operation, the inx2 and
155: * ainx bits in the USER_FPSR are set.
156: *
157: *
158: xdef sintdo
159: sintdo:
160: bfextu FPCR_MODE(a6){2:2},d1 ;use user's mode for rounding
161: * ;implicitly has ext precision
162: * ;in upper word.
163: move.l d1,L_SCR1(a6) ;save mode bits
164: *
165: * Real work of sint is in sintexc
166: *
167: sintexc:
168: bclr.b #sign_bit,LOCAL_EX(a0) ;convert to internal extended
169: * ;format
170: sne LOCAL_SGN(a0)
171: cmp.w #$403e,LOCAL_EX(a0) ;check if (unbiased) exp > 63
172: bgt.b out_rnge ;branch if exp < 63
173: cmp.w #$3ffd,LOCAL_EX(a0) ;check if (unbiased) exp < 0
174: bgt.w in_rnge ;if 63 >= exp > 0, do calc
175: *
176: * Input is less than zero. Restore sign, and check for directed
177: * rounding modes. L_SCR1 contains the rmode in the lower byte.
178: *
179: un_rnge:
180: btst.b #1,L_SCR1+3(a6) ;check for rn and rz
181: beq.b un_rnrz
182: tst.b LOCAL_SGN(a0) ;check for sign
183: bne.b un_rmrp_neg
184: *
185: * Sign is +. If rp, load +1.0, if rm, load +0.0
186: *
187: cmpi.b #3,L_SCR1+3(a6) ;check for rp
188: beq.b un_ldpone ;if rp, load +1.0
189: bsr ld_pzero ;if rm, load +0.0
190: bra t_inx2
191: un_ldpone:
192: bsr ld_pone
193: bra t_inx2
194: *
195: * Sign is -. If rm, load -1.0, if rp, load -0.0
196: *
197: un_rmrp_neg:
198: cmpi.b #2,L_SCR1+3(a6) ;check for rm
199: beq.b un_ldmone ;if rm, load -1.0
200: bsr ld_mzero ;if rp, load -0.0
201: bra t_inx2
202: un_ldmone:
203: bsr ld_mone
204: bra t_inx2
205: *
206: * Rmode is rn or rz; return signed zero
207: *
208: un_rnrz:
209: tst.b LOCAL_SGN(a0) ;check for sign
210: bne.b un_rnrz_neg
211: bsr ld_pzero
212: bra t_inx2
213: un_rnrz_neg:
214: bsr ld_mzero
215: bra t_inx2
216:
217: *
218: * Input is greater than 2^63. All bits are significant. Return
219: * the input.
220: *
221: out_rnge:
222: bfclr LOCAL_SGN(a0){0:8} ;change back to IEEE ext format
223: beq.b intps
224: bset.b #sign_bit,LOCAL_EX(a0)
225: intps:
226: fmove.l fpcr,-(sp)
227: fmove.l #0,fpcr
228: fmove.x LOCAL_EX(a0),fp0 ;if exp > 63
229: * ;then return X to the user
230: * ;there are no fraction bits
231: fmove.l (sp)+,fpcr
232: rts
233:
234: in_rnge:
235: * ;shift off fraction bits
236: clr.l d0 ;clear d0 - initial g,r,s for
237: * ;dnrm_lp
238: move.l #$403e,d1 ;set threshold for dnrm_lp
239: * ;assumes a0 points to operand
240: bsr dnrm_lp
241: * ;returns unnormalized number
242: * ;pointed by a0
243: * ;output d0 supplies g,r,s
244: * ;used by round
245: move.l L_SCR1(a6),d1 ;use selected rounding mode
246: *
247: *
248: bsr round ;round the unnorm based on users
249: * ;input a0 ptr to ext X
250: * ; d0 g,r,s bits
251: * ; d1 PREC/MODE info
252: * ;output a0 ptr to rounded result
253: * ;inexact flag set in USER_FPSR
254: * ;if initial grs set
255: *
256: * normalize the rounded result and store value in fp0
257: *
258: bsr nrm_set ;normalize the unnorm
259: * ;Input: a0 points to operand to
260: * ;be normalized
261: * ;Output: a0 points to normalized
262: * ;result
263: bfclr LOCAL_SGN(a0){0:8}
264: beq.b nrmrndp
265: bset.b #sign_bit,LOCAL_EX(a0) ;return to IEEE extended format
266: nrmrndp:
267: fmove.l fpcr,-(sp)
268: fmove.l #0,fpcr
269: fmove.x LOCAL_EX(a0),fp0 ;move result to fp0
270: fmove.l (sp)+,fpcr
271: rts
272:
273: end