1 | 1 |
2 | sint.sa 3.1 12/10/90 2 | sint.sa 3.1 12/10/90
3 | 3 |
4 | The entry point sINT computes the roun 4 | The entry point sINT computes the rounded integer
5 | equivalent of the input argument, sINT 5 | equivalent of the input argument, sINTRZ computes
6 | the integer rounded to zero of the inp 6 | the integer rounded to zero of the input argument.
7 | 7 |
8 | Entry points sint and sintrz are calle 8 | Entry points sint and sintrz are called from do_func
9 | to emulate the fint and fintrz unimple 9 | to emulate the fint and fintrz unimplemented instructions,
10 | respectively. Entry point sintdo is u 10 | respectively. Entry point sintdo is used by bindec.
11 | 11 |
12 | Input: (Entry points sint and sintrz) 12 | Input: (Entry points sint and sintrz) Double-extended
13 | number X in the ETEMP space in 13 | number X in the ETEMP space in the floating-point
14 | save stack. 14 | save stack.
15 | (Entry point sintdo) Double-ext 15 | (Entry point sintdo) Double-extended number X in
16 | location pointed to by the add 16 | location pointed to by the address register a0.
17 | (Entry point sintd) Double-exte 17 | (Entry point sintd) Double-extended denormalized
18 | number X in the ETEMP space in 18 | number X in the ETEMP space in the floating-point
19 | save stack. 19 | save stack.
20 | 20 |
21 | Output: The function returns int(X) or 21 | Output: The function returns int(X) or intrz(X) in fp0.
22 | 22 |
23 | Modifies: fp0. 23 | Modifies: fp0.
24 | 24 |
25 | Algorithm: (sint and sintrz) 25 | Algorithm: (sint and sintrz)
26 | 26 |
27 | 1. If exp(X) >= 63, return X. 27 | 1. If exp(X) >= 63, return X.
28 | If exp(X) < 0, return +/- 0 or +/- 28 | If exp(X) < 0, return +/- 0 or +/- 1, according to
29 | the rounding mode. 29 | the rounding mode.
30 | 30 |
31 | 2. (X is in range) set rsc = 63 - exp( 31 | 2. (X is in range) set rsc = 63 - exp(X). Unnormalize the
32 | result to the exponent $403e. 32 | result to the exponent $403e.
33 | 33 |
34 | 3. Round the result in the mode given 34 | 3. Round the result in the mode given in USER_FPCR. For
35 | sintrz, force round-to-zero mode. 35 | sintrz, force round-to-zero mode.
36 | 36 |
37 | 4. Normalize the rounded result; store 37 | 4. Normalize the rounded result; store in fp0.
38 | 38 |
39 | For the denormalized cases, force the 39 | For the denormalized cases, force the correct result
40 | for the given sign and rounding mode. 40 | for the given sign and rounding mode.
41 | 41 |
42 | Sign(X) 42 | Sign(X)
43 | RMODE + - 43 | RMODE + -
44 | ----- -------- 44 | ----- --------
45 | RN +0 -0 45 | RN +0 -0
46 | RZ +0 -0 46 | RZ +0 -0
47 | RM +0 -1 47 | RM +0 -1
48 | RP +1 -0 48 | RP +1 -0
49 | 49 |
50 | 50 |
51 | Copyright (C) Motorola, Inc. 1 51 | Copyright (C) Motorola, Inc. 1990
52 | All Rights Reserved 52 | All Rights Reserved
53 | 53 |
54 | For details on the license for this fi 54 | For details on the license for this file, please see the
55 | file, README, in this same directory. 55 | file, README, in this same directory.
56 56
57 |SINT idnt 2,1 | Motorola 040 Floating P 57 |SINT idnt 2,1 | Motorola 040 Floating Point Software Package
58 58
59 |section 8 59 |section 8
60 60
61 #include "fpsp.h" 61 #include "fpsp.h"
62 62
63 |xref dnrm_lp 63 |xref dnrm_lp
64 |xref nrm_set 64 |xref nrm_set
65 |xref round 65 |xref round
66 |xref t_inx2 66 |xref t_inx2
67 |xref ld_pone 67 |xref ld_pone
68 |xref ld_mone 68 |xref ld_mone
69 |xref ld_pzero 69 |xref ld_pzero
70 |xref ld_mzero 70 |xref ld_mzero
71 |xref snzrinx 71 |xref snzrinx
72 72
73 | 73 |
74 | FINT 74 | FINT
75 | 75 |
76 .global sint 76 .global sint
77 sint: 77 sint:
78 bfextu FPCR_MODE(%a6){#2:#2},%d1 78 bfextu FPCR_MODE(%a6){#2:#2},%d1 |use user's mode for rounding
79 | ;impli 79 | ;implicitly has extend precision
80 | ;in up 80 | ;in upper word.
81 movel %d1,L_SCR1(%a6) |save 81 movel %d1,L_SCR1(%a6) |save mode bits
82 bras sintexc 82 bras sintexc
83 83
84 | 84 |
85 | FINT with extended denorm inputs. 85 | FINT with extended denorm inputs.
86 | 86 |
87 .global sintd 87 .global sintd
88 sintd: 88 sintd:
89 btstb #5,FPCR_MODE(%a6) 89 btstb #5,FPCR_MODE(%a6)
90 beq snzrinx |if round near 90 beq snzrinx |if round nearest or round zero, +/- 0
91 btstb #4,FPCR_MODE(%a6) 91 btstb #4,FPCR_MODE(%a6)
92 beqs rnd_mns 92 beqs rnd_mns
93 rnd_pls: 93 rnd_pls:
94 btstb #sign_bit,LOCAL_EX(%a0) 94 btstb #sign_bit,LOCAL_EX(%a0)
95 bnes sintmz 95 bnes sintmz
96 bsr ld_pone |if round plus 96 bsr ld_pone |if round plus inf and pos, answer is +1
97 bra t_inx2 97 bra t_inx2
98 rnd_mns: 98 rnd_mns:
99 btstb #sign_bit,LOCAL_EX(%a0) 99 btstb #sign_bit,LOCAL_EX(%a0)
100 beqs sintpz 100 beqs sintpz
101 bsr ld_mone |if round mns 101 bsr ld_mone |if round mns inf and neg, answer is -1
102 bra t_inx2 102 bra t_inx2
103 sintpz: 103 sintpz:
104 bsr ld_pzero 104 bsr ld_pzero
105 bra t_inx2 105 bra t_inx2
106 sintmz: 106 sintmz:
107 bsr ld_mzero 107 bsr ld_mzero
108 bra t_inx2 108 bra t_inx2
109 109
110 | 110 |
111 | FINTRZ 111 | FINTRZ
112 | 112 |
113 .global sintrz 113 .global sintrz
114 sintrz: 114 sintrz:
115 movel #1,L_SCR1(%a6) |use r 115 movel #1,L_SCR1(%a6) |use rz mode for rounding
116 | ;impli 116 | ;implicitly has extend precision
117 | ;in up 117 | ;in upper word.
118 bras sintexc 118 bras sintexc
119 | 119 |
120 | SINTDO 120 | SINTDO
121 | 121 |
122 | Input: a0 points to an IEEE extended 122 | Input: a0 points to an IEEE extended format operand
123 | Output: fp0 has the result 123 | Output: fp0 has the result
124 | 124 |
125 | Exceptions: 125 | Exceptions:
126 | 126 |
127 | If the subroutine results in an inexact oper 127 | If the subroutine results in an inexact operation, the inx2 and
128 | ainx bits in the USER_FPSR are set. 128 | ainx bits in the USER_FPSR are set.
129 | 129 |
130 | 130 |
131 .global sintdo 131 .global sintdo
132 sintdo: 132 sintdo:
133 bfextu FPCR_MODE(%a6){#2:#2},%d1 133 bfextu FPCR_MODE(%a6){#2:#2},%d1 |use user's mode for rounding
134 | ;impli 134 | ;implicitly has ext precision
135 | ;in up 135 | ;in upper word.
136 movel %d1,L_SCR1(%a6) |save 136 movel %d1,L_SCR1(%a6) |save mode bits
137 | 137 |
138 | Real work of sint is in sintexc 138 | Real work of sint is in sintexc
139 | 139 |
140 sintexc: 140 sintexc:
141 bclrb #sign_bit,LOCAL_EX(%a0) |conve 141 bclrb #sign_bit,LOCAL_EX(%a0) |convert to internal extended
142 | ;forma 142 | ;format
143 sne LOCAL_SGN(%a0) 143 sne LOCAL_SGN(%a0)
144 cmpw #0x403e,LOCAL_EX(%a0) |check 144 cmpw #0x403e,LOCAL_EX(%a0) |check if (unbiased) exp > 63
145 bgts out_rnge 145 bgts out_rnge |branch if exp < 63
146 cmpw #0x3ffd,LOCAL_EX(%a0) |check 146 cmpw #0x3ffd,LOCAL_EX(%a0) |check if (unbiased) exp < 0
147 bgt in_rnge |if 63 147 bgt in_rnge |if 63 >= exp > 0, do calc
148 | 148 |
149 | Input is less than zero. Restore sign, and 149 | Input is less than zero. Restore sign, and check for directed
150 | rounding modes. L_SCR1 contains the rmode i 150 | rounding modes. L_SCR1 contains the rmode in the lower byte.
151 | 151 |
152 un_rnge: 152 un_rnge:
153 btstb #1,L_SCR1+3(%a6) 153 btstb #1,L_SCR1+3(%a6) |check for rn and rz
154 beqs un_rnrz 154 beqs un_rnrz
155 tstb LOCAL_SGN(%a0) |check 155 tstb LOCAL_SGN(%a0) |check for sign
156 bnes un_rmrp_neg 156 bnes un_rmrp_neg
157 | 157 |
158 | Sign is +. If rp, load +1.0, if rm, load +0 158 | Sign is +. If rp, load +1.0, if rm, load +0.0
159 | 159 |
160 cmpib #3,L_SCR1+3(%a6) 160 cmpib #3,L_SCR1+3(%a6) |check for rp
161 beqs un_ldpone |if rp 161 beqs un_ldpone |if rp, load +1.0
162 bsr ld_pzero |if rm 162 bsr ld_pzero |if rm, load +0.0
163 bra t_inx2 163 bra t_inx2
164 un_ldpone: 164 un_ldpone:
165 bsr ld_pone 165 bsr ld_pone
166 bra t_inx2 166 bra t_inx2
167 | 167 |
168 | Sign is -. If rm, load -1.0, if rp, load -0 168 | Sign is -. If rm, load -1.0, if rp, load -0.0
169 | 169 |
170 un_rmrp_neg: 170 un_rmrp_neg:
171 cmpib #2,L_SCR1+3(%a6) 171 cmpib #2,L_SCR1+3(%a6) |check for rm
172 beqs un_ldmone |if rm 172 beqs un_ldmone |if rm, load -1.0
173 bsr ld_mzero |if rp 173 bsr ld_mzero |if rp, load -0.0
174 bra t_inx2 174 bra t_inx2
175 un_ldmone: 175 un_ldmone:
176 bsr ld_mone 176 bsr ld_mone
177 bra t_inx2 177 bra t_inx2
178 | 178 |
179 | Rmode is rn or rz; return signed zero 179 | Rmode is rn or rz; return signed zero
180 | 180 |
181 un_rnrz: 181 un_rnrz:
182 tstb LOCAL_SGN(%a0) |check 182 tstb LOCAL_SGN(%a0) |check for sign
183 bnes un_rnrz_neg 183 bnes un_rnrz_neg
184 bsr ld_pzero 184 bsr ld_pzero
185 bra t_inx2 185 bra t_inx2
186 un_rnrz_neg: 186 un_rnrz_neg:
187 bsr ld_mzero 187 bsr ld_mzero
188 bra t_inx2 188 bra t_inx2
189 189
190 | 190 |
191 | Input is greater than 2^63. All bits are si 191 | Input is greater than 2^63. All bits are significant. Return
192 | the input. 192 | the input.
193 | 193 |
194 out_rnge: 194 out_rnge:
195 bfclr LOCAL_SGN(%a0){#0:#8} |chang 195 bfclr LOCAL_SGN(%a0){#0:#8} |change back to IEEE ext format
196 beqs intps 196 beqs intps
197 bsetb #sign_bit,LOCAL_EX(%a0) 197 bsetb #sign_bit,LOCAL_EX(%a0)
198 intps: 198 intps:
199 fmovel %fpcr,-(%sp) 199 fmovel %fpcr,-(%sp)
200 fmovel #0,%fpcr 200 fmovel #0,%fpcr
201 fmovex LOCAL_EX(%a0),%fp0 |if ex 201 fmovex LOCAL_EX(%a0),%fp0 |if exp > 63
202 | ;then 202 | ;then return X to the user
203 | ;there 203 | ;there are no fraction bits
204 fmovel (%sp)+,%fpcr 204 fmovel (%sp)+,%fpcr
205 rts 205 rts
206 206
207 in_rnge: 207 in_rnge:
208 | ;shift 208 | ;shift off fraction bits
209 clrl %d0 |clear 209 clrl %d0 |clear d0 - initial g,r,s for
210 | ;dnrm_ 210 | ;dnrm_lp
211 movel #0x403e,%d1 |set t 211 movel #0x403e,%d1 |set threshold for dnrm_lp
212 | ;assum 212 | ;assumes a0 points to operand
213 bsr dnrm_lp 213 bsr dnrm_lp
214 | ;retur 214 | ;returns unnormalized number
215 | ;point 215 | ;pointed by a0
216 | ;outpu 216 | ;output d0 supplies g,r,s
217 | ;used 217 | ;used by round
218 movel L_SCR1(%a6),%d1 |use s 218 movel L_SCR1(%a6),%d1 |use selected rounding mode
219 | 219 |
220 | 220 |
221 bsr round |round 221 bsr round |round the unnorm based on users
222 | ;input 222 | ;input a0 ptr to ext X
223 | ; 223 | ; d0 g,r,s bits
224 | ; 224 | ; d1 PREC/MODE info
225 | ;outpu 225 | ;output a0 ptr to rounded result
226 | ;inexa 226 | ;inexact flag set in USER_FPSR
227 | ;if in 227 | ;if initial grs set
228 | 228 |
229 | normalize the rounded result and store value 229 | normalize the rounded result and store value in fp0
230 | 230 |
231 bsr nrm_set |norma 231 bsr nrm_set |normalize the unnorm
232 | ;Input 232 | ;Input: a0 points to operand to
233 | ;be no 233 | ;be normalized
234 | ;Outpu 234 | ;Output: a0 points to normalized
235 | ;resul 235 | ;result
236 bfclr LOCAL_SGN(%a0){#0:#8} 236 bfclr LOCAL_SGN(%a0){#0:#8}
237 beqs nrmrndp 237 beqs nrmrndp
238 bsetb #sign_bit,LOCAL_EX(%a0) |retur 238 bsetb #sign_bit,LOCAL_EX(%a0) |return to IEEE extended format
239 nrmrndp: 239 nrmrndp:
240 fmovel %fpcr,-(%sp) 240 fmovel %fpcr,-(%sp)
241 fmovel #0,%fpcr 241 fmovel #0,%fpcr
242 fmovex LOCAL_EX(%a0),%fp0 |move 242 fmovex LOCAL_EX(%a0),%fp0 |move result to fp0
243 fmovel (%sp)+,%fpcr 243 fmovel (%sp)+,%fpcr
244 rts 244 rts
245 245
246 |end 246 |end
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