1 |
2 | binstr.sa 3.3 12/19/90
3 |
4 |
5 | Description: Converts a 64-bit binary
6 |
7 | Input: 64-bit binary integer in d2:d3,
8 | d0, and a pointer to start in memo
9 | in d0. (This pointer must point to
10 | lword of the packed decimal memory
11 |
12 | Output: LEN bcd digits representing th
13 |
14 | Algorithm:
15 | The 64-bit binary is assumed t
16 | bit 63. The fraction is multi
17 | shift and a mul by 8 shift. T
18 | msb form a decimal digit. Thi
19 | LEN digits are formed.
20 |
21 | A1. Init d7 to 1. D7 is the byte digi
22 | digit formed will be assumed t
23 | to force the first byte formed
24 |
25 | A2. Beginning of the loop:
26 | Copy the fraction in d2:d3 to
27 |
28 | A3. Multiply the fraction in d2:d3 by
29 | extracts and shifts. The thre
30 | d1.
31 |
32 | A4. Multiply the fraction in d4:d5 by
33 | will be collected by the carry
34 |
35 | A5. Add using the carry the 64-bit qua
36 | into d2:d3. D1 will contain t
37 |
38 | A6. Test d7. If zero, the digit forme
39 | zero, it is the ls digit. Put
40 | upper word of d0. If it is th
41 | from d0 to memory.
42 |
43 | A7. Decrement d6 (LEN counter) and rep
44 |
45 | Implementation Notes:
46 |
47 | The registers are used as follows:
48 |
49 | d0: LEN counter
50 | d1: temp used to form the digi
51 | d2: upper 32-bits of fraction
52 | d3: lower 32-bits of fraction
53 | d4: upper 32-bits of fraction
54 | d5: lower 32-bits of fraction
55 | d6: temp for bit-field extract
56 | d7: byte digit formation word;
57 | a0: pointer into memory for pa
58 |
59
60 | Copyright (C) Motorola, Inc. 1
61 | All Rights Reserved
62 |
63 | For details on the license for this fi
64 | file, README, in this same directory.
65
66 |BINSTR idnt 2,1 | Motorola 040 Floating
67
68 |section 8
69
70 #include "fpsp.h"
71
72 .global binstr
73 binstr:
74 moveml %d0-%d7,-(%a7)
75 |
76 | A1: Init d7
77 |
78 moveql #1,%d7 |init
79 subql #1,%d0 |for d
80 |
81 | A2. Copy d2:d3 to d4:d5. Start loop.
82 |
83 loop:
84 movel %d2,%d4 |copy
85 movel %d3,%d5 |to d4
86 |
87 | A3. Multiply d2:d3 by 8; extract msbs into d
88 |
89 bfextu %d2{#0:#3},%d1 |copy
90 asll #3,%d2 |shift
91 bfextu %d3{#0:#3},%d6 |copy
92 asll #3,%d3 |shift
93 orl %d6,%d2 |or in
94 |
95 | A4. Multiply d4:d5 by 2; add carry out to d1
96 |
97 asll #1,%d5 |mul d
98 roxll #1,%d4 |mul d
99 swap %d6 |put 0
100 addxw %d6,%d1 |add i
101 |
102 | A5. Add mul by 8 to mul by 2. D1 contains t
103 |
104 addl %d5,%d3 |add l
105 nop |ERRAT
106 addxl %d4,%d2 |add w
107 nop |ERRAT
108 addxw %d6,%d1 |add i
109 swap %d6 |with
110 |
111 | A6. Test d7 and branch.
112 |
113 tstw %d7 |if ze
114 beqs first_d |if no
115 sec_d:
116 swap %d7 |bring
117 aslw #4,%d7 |first
118 addw %d1,%d7 |add i
119 moveb %d7,(%a0)+ |store
120 swap %d7 |put L
121 clrw %d7 |set d
122 dbf %d0,loop |do lo
123 bras end_bstr |finis
124 first_d:
125 swap %d7 |put d
126 movew %d1,%d7 |put n
127 swap %d7 |put L
128 addqw #1,%d7 |set d
129 dbf %d0,loop |do lo
130 swap %d7 |put l
131 lslw #4,%d7 |move
132 moveb %d7,(%a0)+ |store
133 |
134 | Clean up and return with result in fp0.
135 |
136 end_bstr:
137 moveml (%a7)+,%d0-%d7
138 rts
139 |end
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