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1|
2| x_store.sa 3.2 1/24/91
3|
4| store --- store operand to memory or register
5|
6| Used by underflow and overflow handlers.
7|
8| a6 = points to fp value to be stored.
9|
10
11| Copyright (C) Motorola, Inc. 1990
12| All Rights Reserved
13|
14| THIS IS UNPUBLISHED PROPRIETARY SOURCE CODE OF MOTOROLA
15| The copyright notice above does not evidence any
16| actual or intended publication of such source code.
17
18X_STORE: |idnt 2,1 | Motorola 040 Floating Point Software Package
19
20 |section 8
21
22fpreg_mask:
23 .byte 0x80,0x40,0x20,0x10,0x08,0x04,0x02,0x01
24
25#include "fpsp.h"
26
27 |xref mem_write
28 |xref get_fline
29 |xref g_opcls
30 |xref g_dfmtou
31 |xref reg_dest
32
33 .global dest_ext
34 .global dest_dbl
35 .global dest_sgl
36
37 .global store
38store:
39 btstb #E3,E_BYTE(%a6)
40 beqs E1_sto
41E3_sto:
42 movel CMDREG3B(%a6),%d0
43 bfextu %d0{#6:#3},%d0 |isolate dest. reg from cmdreg3b
44sto_fp:
45 lea fpreg_mask,%a1
46 moveb (%a1,%d0.w),%d0 |convert reg# to dynamic register mask
47 tstb LOCAL_SGN(%a0)
48 beqs is_pos
49 bsetb #sign_bit,LOCAL_EX(%a0)
50is_pos:
51 fmovemx (%a0),%d0 |move to correct register
52|
53| if fp0-fp3 is being modified, we must put a copy
54| in the USER_FPn variable on the stack because all exception
55| handlers restore fp0-fp3 from there.
56|
57 cmpb #0x80,%d0
58 bnes not_fp0
59 fmovemx %fp0-%fp0,USER_FP0(%a6)
60 rts
61not_fp0:
62 cmpb #0x40,%d0
63 bnes not_fp1
64 fmovemx %fp1-%fp1,USER_FP1(%a6)
65 rts
66not_fp1:
67 cmpb #0x20,%d0
68 bnes not_fp2
69 fmovemx %fp2-%fp2,USER_FP2(%a6)
70 rts
71not_fp2:
72 cmpb #0x10,%d0
73 bnes not_fp3
74 fmovemx %fp3-%fp3,USER_FP3(%a6)
75 rts
76not_fp3:
77 rts
78
79E1_sto:
80 bsrl g_opcls |returns opclass in d0
81 cmpib #3,%d0
82 beq opc011 |branch if opclass 3
83 movel CMDREG1B(%a6),%d0
84 bfextu %d0{#6:#3},%d0 |extract destination register
85 bras sto_fp
86
87opc011:
88 bsrl g_dfmtou |returns dest format in d0
89| ;ext=00, sgl=01, dbl=10
90 movel %a0,%a1 |save source addr in a1
91 movel EXC_EA(%a6),%a0 |get the address
92 cmpil #0,%d0 |if dest format is extended
93 beq dest_ext |then branch
94 cmpil #1,%d0 |if dest format is single
95 beq dest_sgl |then branch
96|
97| fall through to dest_dbl
98|
99
100|
101| dest_dbl --- write double precision value to user space
102|
103|Input
104| a0 -> destination address
105| a1 -> source in extended precision
106|Output
107| a0 -> destroyed
108| a1 -> destroyed
109| d0 -> 0
110|
111|Changes extended precision to double precision.
112| Note: no attempt is made to round the extended value to double.
113| dbl_sign = ext_sign
114| dbl_exp = ext_exp - $3fff(ext bias) + $7ff(dbl bias)
115| get rid of ext integer bit
116| dbl_mant = ext_mant{62:12}
117|
118| --------------- --------------- ---------------
119| extended -> |s| exp | |1| ms mant | | ls mant |
120| --------------- --------------- ---------------
121| 95 64 63 62 32 31 11 0
122| | |
123| | |
124| | |
125| v v
126| --------------- ---------------
127| double -> |s|exp| mant | | mant |
128| --------------- ---------------
129| 63 51 32 31 0
130|
131dest_dbl:
132 clrl %d0 |clear d0
133 movew LOCAL_EX(%a1),%d0 |get exponent
134 subw #0x3fff,%d0 |subtract extended precision bias
135 cmpw #0x4000,%d0 |check if inf
136 beqs inf |if so, special case
137 addw #0x3ff,%d0 |add double precision bias
138 swap %d0 |d0 now in upper word
139 lsll #4,%d0 |d0 now in proper place for dbl prec exp
140 tstb LOCAL_SGN(%a1)
141 beqs get_mant |if positive, go process mantissa
142 bsetl #31,%d0 |if negative, put in sign information
143| ; before continuing
144 bras get_mant |go process mantissa
145inf:
146 movel #0x7ff00000,%d0 |load dbl inf exponent
147 clrl LOCAL_HI(%a1) |clear msb
148 tstb LOCAL_SGN(%a1)
149 beqs dbl_inf |if positive, go ahead and write it
150 bsetl #31,%d0 |if negative put in sign information
151dbl_inf:
152 movel %d0,LOCAL_EX(%a1) |put the new exp back on the stack
153 bras dbl_wrt
154get_mant:
155 movel LOCAL_HI(%a1),%d1 |get ms mantissa
156 bfextu %d1{#1:#20},%d1 |get upper 20 bits of ms
157 orl %d1,%d0 |put these bits in ms word of double
158 movel %d0,LOCAL_EX(%a1) |put the new exp back on the stack
159 movel LOCAL_HI(%a1),%d1 |get ms mantissa
160 movel #21,%d0 |load shift count
161 lsll %d0,%d1 |put lower 11 bits in upper bits
162 movel %d1,LOCAL_HI(%a1) |build lower lword in memory
163 movel LOCAL_LO(%a1),%d1 |get ls mantissa
164 bfextu %d1{#0:#21},%d0 |get ls 21 bits of double
165 orl %d0,LOCAL_HI(%a1) |put them in double result
166dbl_wrt:
167 movel #0x8,%d0 |byte count for double precision number
168 exg %a0,%a1 |a0=supervisor source, a1=user dest
169 bsrl mem_write |move the number to the user's memory
170 rts
171|
172| dest_sgl --- write single precision value to user space
173|
174|Input
175| a0 -> destination address
176| a1 -> source in extended precision
177|
178|Output
179| a0 -> destroyed
180| a1 -> destroyed
181| d0 -> 0
182|
183|Changes extended precision to single precision.
184| sgl_sign = ext_sign
185| sgl_exp = ext_exp - $3fff(ext bias) + $7f(sgl bias)
186| get rid of ext integer bit
187| sgl_mant = ext_mant{62:12}
188|
189| --------------- --------------- ---------------
190| extended -> |s| exp | |1| ms mant | | ls mant |
191| --------------- --------------- ---------------
192| 95 64 63 62 40 32 31 12 0
193| | |
194| | |
195| | |
196| v v
197| ---------------
198| single -> |s|exp| mant |
199| ---------------
200| 31 22 0
201|
202dest_sgl:
203 clrl %d0
204 movew LOCAL_EX(%a1),%d0 |get exponent
205 subw #0x3fff,%d0 |subtract extended precision bias
206 cmpw #0x4000,%d0 |check if inf
207 beqs sinf |if so, special case
208 addw #0x7f,%d0 |add single precision bias
209 swap %d0 |put exp in upper word of d0
210 lsll #7,%d0 |shift it into single exp bits
211 tstb LOCAL_SGN(%a1)
212 beqs get_sman |if positive, continue
213 bsetl #31,%d0 |if negative, put in sign first
214 bras get_sman |get mantissa
215sinf:
216 movel #0x7f800000,%d0 |load single inf exp to d0
217 tstb LOCAL_SGN(%a1)
218 beqs sgl_wrt |if positive, continue
219 bsetl #31,%d0 |if negative, put in sign info
220 bras sgl_wrt
221
222get_sman:
223 movel LOCAL_HI(%a1),%d1 |get ms mantissa
224 bfextu %d1{#1:#23},%d1 |get upper 23 bits of ms
225 orl %d1,%d0 |put these bits in ms word of single
226
227sgl_wrt:
228 movel %d0,L_SCR1(%a6) |put the new exp back on the stack
229 movel #0x4,%d0 |byte count for single precision number
230 tstl %a0 |users destination address
231 beqs sgl_Dn |destination is a data register
232 exg %a0,%a1 |a0=supervisor source, a1=user dest
233 leal L_SCR1(%a6),%a0 |point a0 to data
234 bsrl mem_write |move the number to the user's memory
235 rts
236sgl_Dn:
237 bsrl get_fline |returns fline word in d0
238 andw #0x7,%d0 |isolate register number
239 movel %d0,%d1 |d1 has size:reg formatted for reg_dest
240 orl #0x10,%d1 |reg_dest wants size added to reg#
241 bral reg_dest |size is X, rts in reg_dest will
242| ;return to caller of dest_sgl
243
244dest_ext:
245 tstb LOCAL_SGN(%a1) |put back sign into exponent word
246 beqs dstx_cont
247 bsetb #sign_bit,LOCAL_EX(%a1)
248dstx_cont:
249 clrb LOCAL_SGN(%a1) |clear out the sign byte
250
251 movel #0x0c,%d0 |byte count for extended number
252 exg %a0,%a1 |a0=supervisor source, a1=user dest
253 bsrl mem_write |move the number to the user's memory
254 rts
255
256 |end
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