URL https://opencores.org/ocsvn/or1k/or1k/trunk

Subversion Repositories or1k

[/] [or1k/] [trunk/] [rc203soc/] [sw/] [uClinux/] [arch/] [sparc/] [lib/] [rem.S] - Blame information for rev 1765

Details | Compare with Previous | View Log


/* $Id: rem.S,v 1.1 2005-12-20 09:50:47 jcastillo Exp $
 * rem.S:       This routine was taken from glibc-1.09 and is covered
 *              by the GNU Library General Public License Version 2.
 */
 
 
/* This file is generated from divrem.m4; DO NOT EDIT! */
/*
 * Division and remainder, from Appendix E of the Sparc Version 8
 * Architecture Manual, with fixes from Gordon Irlam.
 */
 
/*
 * Input: dividend and divisor in %o0 and %o1 respectively.
 *
 * m4 parameters:
 *  .rem        name of function to generate
 *  rem         rem=div => %o0 / %o1; rem=rem => %o0 % %o1
 *  true                true=true => signed; true=false => unsigned
 *
 * Algorithm parameters:
 *  N           how many bits per iteration we try to get (4)
 *  WORDSIZE    total number of bits (32)
 *
 * Derived constants:
 *  TOPBITS     number of bits in the top decade of a number
 *
 * Important variables:
 *  Q           the partial quotient under development (initially 0)
 *  R           the remainder so far, initially the dividend
 *  ITER        number of main division loop iterations required;
 *              equal to ceil(log2(quotient) / N).  Note that this
 *              is the log base (2^N) of the quotient.
 *  V           the current comparand, initially divisor*2^(ITER*N-1)
 *
 * Cost:
 *  Current estimate for non-large dividend is
 *      ceil(log2(quotient) / N) * (10 + 7N/2) + C
 *  A large dividend is one greater than 2^(31-TOPBITS) and takes a
 *  different path, as the upper bits of the quotient must be developed
 *  one bit at a time.
 */
 
 
        .globl .rem
.rem:
        ! compute sign of result; if neither is negative, no problem
        orcc    %o1, %o0, %g0   ! either negative?
        bge     2f                      ! no, go do the divide
        xor     %o1, %o0, %g6   ! compute sign in any case
        tst     %o1
        bge     1f
        tst     %o0
        ! %o1 is definitely negative; %o0 might also be negative
        bge     2f                      ! if %o0 not negative...
        sub     %g0, %o1, %o1   ! in any case, make %o1 nonneg
1:      ! %o0 is negative, %o1 is nonnegative
        sub     %g0, %o0, %o0   ! make %o0 nonnegative
2:
 
        ! Ready to divide.  Compute size of quotient; scale comparand.
        orcc    %o1, %g0, %o5
        bne     1f
        mov     %o0, %o3
 
                ! Divide by zero trap.  If it returns, return 0 (about as
                ! wrong as possible, but that is what SunOS does...).
                ta      ST_DIV0
                retl
                clr     %o0
 
1:
        cmp     %o3, %o5                        ! if %o1 exceeds %o0, done
        blu     Lgot_result             ! (and algorithm fails otherwise)
        clr     %o2
        sethi   %hi(1 << (32 - 4 - 1)), %g1
        cmp     %o3, %g1
        blu     Lnot_really_big
        clr     %o4
 
        ! Here the dividend is >= 2**(31-N) or so.  We must be careful here,
        ! as our usual N-at-a-shot divide step will cause overflow and havoc.
        ! The number of bits in the result here is N*ITER+SC, where SC <= N.
        ! Compute ITER in an unorthodox manner: know we need to shift V into
        ! the top decade: so do not even bother to compare to R.
        1:
                cmp     %o5, %g1
                bgeu    3f
                mov     1, %g7
                sll     %o5, 4, %o5
                b       1b
                add     %o4, 1, %o4
 
        ! Now compute %g7.
        2:      addcc   %o5, %o5, %o5
                bcc     Lnot_too_big
                add     %g7, 1, %g7
 
                ! We get here if the %o1 overflowed while shifting.
                ! This means that %o3 has the high-order bit set.
                ! Restore %o5 and subtract from %o3.
                sll     %g1, 4, %g1     ! high order bit
                srl     %o5, 1, %o5             ! rest of %o5
                add     %o5, %g1, %o5
                b       Ldo_single_div
                sub     %g7, 1, %g7
 
        Lnot_too_big:
        3:      cmp     %o5, %o3
                blu     2b
                nop
                be      Ldo_single_div
                nop
        /* NB: these are commented out in the V8-Sparc manual as well */
        /* (I do not understand this) */
        ! %o5 > %o3: went too far: back up 1 step
        !       srl     %o5, 1, %o5
        !       dec     %g7
        ! do single-bit divide steps
        !
        ! We have to be careful here.  We know that %o3 >= %o5, so we can do the
        ! first divide step without thinking.  BUT, the others are conditional,
        ! and are only done if %o3 >= 0.  Because both %o3 and %o5 may have the high-
        ! order bit set in the first step, just falling into the regular
        ! division loop will mess up the first time around.
        ! So we unroll slightly...
        Ldo_single_div:
                subcc   %g7, 1, %g7
                bl      Lend_regular_divide
                nop
                sub     %o3, %o5, %o3
                mov     1, %o2
                b       Lend_single_divloop
                nop
        Lsingle_divloop:
                sll     %o2, 1, %o2
                bl      1f
                srl     %o5, 1, %o5
                ! %o3 >= 0
                sub     %o3, %o5, %o3
                b       2f
                add     %o2, 1, %o2
        1:      ! %o3 < 0
                add     %o3, %o5, %o3
                sub     %o2, 1, %o2
        2:
        Lend_single_divloop:
                subcc   %g7, 1, %g7
                bge     Lsingle_divloop
                tst     %o3
                b,a     Lend_regular_divide
 
Lnot_really_big:
1:
        sll     %o5, 4, %o5
        cmp     %o5, %o3
        bleu    1b
        addcc   %o4, 1, %o4
        be      Lgot_result
        sub     %o4, 1, %o4
 
        tst     %o3     ! set up for initial iteration
Ldivloop:
        sll     %o2, 4, %o2
                ! depth 1, accumulated bits 0
        bl      L.1.16
        srl     %o5,1,%o5
        ! remainder is positive
        subcc   %o3,%o5,%o3
                        ! depth 2, accumulated bits 1
        bl      L.2.17
        srl     %o5,1,%o5
        ! remainder is positive
        subcc   %o3,%o5,%o3
                        ! depth 3, accumulated bits 3
        bl      L.3.19
        srl     %o5,1,%o5
        ! remainder is positive
        subcc   %o3,%o5,%o3
                        ! depth 4, accumulated bits 7
        bl      L.4.23
        srl     %o5,1,%o5
        ! remainder is positive
        subcc   %o3,%o5,%o3
                b       9f
                add     %o2, (7*2+1), %o2
 
L.4.23:
        ! remainder is negative
        addcc   %o3,%o5,%o3
                b       9f
                add     %o2, (7*2-1), %o2
 
 
L.3.19:
        ! remainder is negative
        addcc   %o3,%o5,%o3
                        ! depth 4, accumulated bits 5
        bl      L.4.21
        srl     %o5,1,%o5
        ! remainder is positive
        subcc   %o3,%o5,%o3
                b       9f
                add     %o2, (5*2+1), %o2
 
L.4.21:
        ! remainder is negative
        addcc   %o3,%o5,%o3
                b       9f
                add     %o2, (5*2-1), %o2
 
 
 
L.2.17:
        ! remainder is negative
        addcc   %o3,%o5,%o3
                        ! depth 3, accumulated bits 1
        bl      L.3.17
        srl     %o5,1,%o5
        ! remainder is positive
        subcc   %o3,%o5,%o3
                        ! depth 4, accumulated bits 3
        bl      L.4.19
        srl     %o5,1,%o5
        ! remainder is positive
        subcc   %o3,%o5,%o3
                b       9f
                add     %o2, (3*2+1), %o2
 
L.4.19:
        ! remainder is negative
        addcc   %o3,%o5,%o3
                b       9f
                add     %o2, (3*2-1), %o2
 
 
L.3.17:
        ! remainder is negative
        addcc   %o3,%o5,%o3
                        ! depth 4, accumulated bits 1
        bl      L.4.17
        srl     %o5,1,%o5
        ! remainder is positive
        subcc   %o3,%o5,%o3
                b       9f
                add     %o2, (1*2+1), %o2
 
L.4.17:
        ! remainder is negative
        addcc   %o3,%o5,%o3
                b       9f
                add     %o2, (1*2-1), %o2
 
 
 
 
L.1.16:
        ! remainder is negative
        addcc   %o3,%o5,%o3
                        ! depth 2, accumulated bits -1
        bl      L.2.15
        srl     %o5,1,%o5
        ! remainder is positive
        subcc   %o3,%o5,%o3
                        ! depth 3, accumulated bits -1
        bl      L.3.15
        srl     %o5,1,%o5
        ! remainder is positive
        subcc   %o3,%o5,%o3
                        ! depth 4, accumulated bits -1
        bl      L.4.15
        srl     %o5,1,%o5
        ! remainder is positive
        subcc   %o3,%o5,%o3
                b       9f
                add     %o2, (-1*2+1), %o2
 
L.4.15:
        ! remainder is negative
        addcc   %o3,%o5,%o3
                b       9f
                add     %o2, (-1*2-1), %o2
 
 
L.3.15:
        ! remainder is negative
        addcc   %o3,%o5,%o3
                        ! depth 4, accumulated bits -3
        bl      L.4.13
        srl     %o5,1,%o5
        ! remainder is positive
        subcc   %o3,%o5,%o3
                b       9f
                add     %o2, (-3*2+1), %o2
 
L.4.13:
        ! remainder is negative
        addcc   %o3,%o5,%o3
                b       9f
                add     %o2, (-3*2-1), %o2
 
 
 
L.2.15:
        ! remainder is negative
        addcc   %o3,%o5,%o3
                        ! depth 3, accumulated bits -3
        bl      L.3.13
        srl     %o5,1,%o5
        ! remainder is positive
        subcc   %o3,%o5,%o3
                        ! depth 4, accumulated bits -5
        bl      L.4.11
        srl     %o5,1,%o5
        ! remainder is positive
        subcc   %o3,%o5,%o3
                b       9f
                add     %o2, (-5*2+1), %o2
 
L.4.11:
        ! remainder is negative
        addcc   %o3,%o5,%o3
                b       9f
                add     %o2, (-5*2-1), %o2
 
 
L.3.13:
        ! remainder is negative
        addcc   %o3,%o5,%o3
                        ! depth 4, accumulated bits -7
        bl      L.4.9
        srl     %o5,1,%o5
        ! remainder is positive
        subcc   %o3,%o5,%o3
                b       9f
                add     %o2, (-7*2+1), %o2
 
L.4.9:
        ! remainder is negative
        addcc   %o3,%o5,%o3
                b       9f
                add     %o2, (-7*2-1), %o2
 
 
 
 
        9:
Lend_regular_divide:
        subcc   %o4, 1, %o4
        bge     Ldivloop
        tst     %o3
        bl,a    Lgot_result
        ! non-restoring fixup here (one instruction only!)
        add     %o3, %o1, %o3
 
 
Lgot_result:
 
        retl
        mov %o3, %o0

Browse

Tools

Subversion Repositories or1k

[/] [or1k/] [trunk/] [rc203soc/] [sw/] [uClinux/] [arch/] [sparc/] [lib/] [rem.S] - Blame information for rev 1765

Line No.	Rev	Author	Line
1	1624	jcastillo	`/* $Id: rem.S,v 1.1 2005-12-20 09:50:47 jcastillo Exp $`
2			`* rem.S: This routine was taken from glibc-1.09 and is covered`
3			`* by the GNU Library General Public License Version 2.`
4			`*/`
5
6
7			`/* This file is generated from divrem.m4; DO NOT EDIT! */`
8			`/*`
9			`* Division and remainder, from Appendix E of the Sparc Version 8`
10			`* Architecture Manual, with fixes from Gordon Irlam.`
11			`*/`
12
13			`/*`
14			`* Input: dividend and divisor in %o0 and %o1 respectively.`
15			`*`
16			`* m4 parameters:`
17			`* .rem name of function to generate`
18			`* rem rem=div => %o0 / %o1; rem=rem => %o0 % %o1`
19			`* true true=true => signed; true=false => unsigned`
20			`*`
21			`* Algorithm parameters:`
22			`* N how many bits per iteration we try to get (4)`
23			`* WORDSIZE total number of bits (32)`
24			`*`
25			`* Derived constants:`
26			`* TOPBITS number of bits in the top decade of a number`
27			`*`
28			`* Important variables:`
29			`* Q the partial quotient under development (initially 0)`
30			`* R the remainder so far, initially the dividend`
31			`* ITER number of main division loop iterations required;`
32			`* equal to ceil(log2(quotient) / N). Note that this`
33			`* is the log base (2^N) of the quotient.`
34			`* V the current comparand, initially divisor2^(ITERN-1)`
35			`*`
36			`* Cost:`
37			`* Current estimate for non-large dividend is`
38			`* ceil(log2(quotient) / N) * (10 + 7N/2) + C`
39			`* A large dividend is one greater than 2^(31-TOPBITS) and takes a`
40			`* different path, as the upper bits of the quotient must be developed`
41			`* one bit at a time.`
42			`*/`
43
44
45			`.globl .rem`
46			`.rem:`
47			`! compute sign of result; if neither is negative, no problem`
48			`orcc %o1, %o0, %g0 ! either negative?`
49			`bge 2f ! no, go do the divide`
50			`xor %o1, %o0, %g6 ! compute sign in any case`
51			`tst %o1`
52			`bge 1f`
53			`tst %o0`
54			`! %o1 is definitely negative; %o0 might also be negative`
55			`bge 2f ! if %o0 not negative...`
56			`sub %g0, %o1, %o1 ! in any case, make %o1 nonneg`
57			`1: ! %o0 is negative, %o1 is nonnegative`
58			`sub %g0, %o0, %o0 ! make %o0 nonnegative`
59			`2:`
60
61			`! Ready to divide. Compute size of quotient; scale comparand.`
62			`orcc %o1, %g0, %o5`
63			`bne 1f`
64			`mov %o0, %o3`
65
66			`! Divide by zero trap. If it returns, return 0 (about as`
67			`! wrong as possible, but that is what SunOS does...).`
68			`ta ST_DIV0`
69			`retl`
70			`clr %o0`
71
72			`1:`
73			`cmp %o3, %o5 ! if %o1 exceeds %o0, done`
74			`blu Lgot_result ! (and algorithm fails otherwise)`
75			`clr %o2`
76			`sethi %hi(1 << (32 - 4 - 1)), %g1`
77			`cmp %o3, %g1`
78			`blu Lnot_really_big`
79			`clr %o4`
80
81			`! Here the dividend is >= 2**(31-N) or so. We must be careful here,`
82			`! as our usual N-at-a-shot divide step will cause overflow and havoc.`
83			`! The number of bits in the result here is N*ITER+SC, where SC <= N.`
84			`! Compute ITER in an unorthodox manner: know we need to shift V into`
85			`! the top decade: so do not even bother to compare to R.`
86			`1:`
87			`cmp %o5, %g1`
88			`bgeu 3f`
89			`mov 1, %g7`
90			`sll %o5, 4, %o5`
91			`b 1b`
92			`add %o4, 1, %o4`
93
94			`! Now compute %g7.`
95			`2: addcc %o5, %o5, %o5`
96			`bcc Lnot_too_big`
97			`add %g7, 1, %g7`
98
99			`! We get here if the %o1 overflowed while shifting.`
100			`! This means that %o3 has the high-order bit set.`
101			`! Restore %o5 and subtract from %o3.`
102			`sll %g1, 4, %g1 ! high order bit`
103			`srl %o5, 1, %o5 ! rest of %o5`
104			`add %o5, %g1, %o5`
105			`b Ldo_single_div`
106			`sub %g7, 1, %g7`
107
108			`Lnot_too_big:`
109			`3: cmp %o5, %o3`
110			`blu 2b`
111			`nop`
112			`be Ldo_single_div`
113			`nop`
114			`/* NB: these are commented out in the V8-Sparc manual as well */`
115			`/* (I do not understand this) */`
116			`! %o5 > %o3: went too far: back up 1 step`
117			`! srl %o5, 1, %o5`
118			`! dec %g7`
119			`! do single-bit divide steps`
120			`!`
121			`! We have to be careful here. We know that %o3 >= %o5, so we can do the`
122			`! first divide step without thinking. BUT, the others are conditional,`
123			`! and are only done if %o3 >= 0. Because both %o3 and %o5 may have the high-`
124			`! order bit set in the first step, just falling into the regular`
125			`! division loop will mess up the first time around.`
126			`! So we unroll slightly...`
127			`Ldo_single_div:`
128			`subcc %g7, 1, %g7`
129			`bl Lend_regular_divide`
130			`nop`
131			`sub %o3, %o5, %o3`
132			`mov 1, %o2`
133			`b Lend_single_divloop`
134			`nop`
135			`Lsingle_divloop:`
136			`sll %o2, 1, %o2`
137			`bl 1f`
138			`srl %o5, 1, %o5`
139			`! %o3 >= 0`
140			`sub %o3, %o5, %o3`
141			`b 2f`
142			`add %o2, 1, %o2`
143			`1: ! %o3 < 0`
144			`add %o3, %o5, %o3`
145			`sub %o2, 1, %o2`
146			`2:`
147			`Lend_single_divloop:`
148			`subcc %g7, 1, %g7`
149			`bge Lsingle_divloop`
150			`tst %o3`
151			`b,a Lend_regular_divide`
152
153			`Lnot_really_big:`
154			`1:`
155			`sll %o5, 4, %o5`
156			`cmp %o5, %o3`
157			`bleu 1b`
158			`addcc %o4, 1, %o4`
159			`be Lgot_result`
160			`sub %o4, 1, %o4`
161
162			`tst %o3 ! set up for initial iteration`
163			`Ldivloop:`
164			`sll %o2, 4, %o2`
165			`! depth 1, accumulated bits 0`
166			`bl L.1.16`
167			`srl %o5,1,%o5`
168			`! remainder is positive`
169			`subcc %o3,%o5,%o3`
170			`! depth 2, accumulated bits 1`
171			`bl L.2.17`
172			`srl %o5,1,%o5`
173			`! remainder is positive`
174			`subcc %o3,%o5,%o3`
175			`! depth 3, accumulated bits 3`
176			`bl L.3.19`
177			`srl %o5,1,%o5`
178			`! remainder is positive`
179			`subcc %o3,%o5,%o3`
180			`! depth 4, accumulated bits 7`
181			`bl L.4.23`
182			`srl %o5,1,%o5`
183			`! remainder is positive`
184			`subcc %o3,%o5,%o3`
185			`b 9f`
186			`add %o2, (7*2+1), %o2`
187
188			`L.4.23:`
189			`! remainder is negative`
190			`addcc %o3,%o5,%o3`
191			`b 9f`
192			`add %o2, (7*2-1), %o2`
193
194
195			`L.3.19:`
196			`! remainder is negative`
197			`addcc %o3,%o5,%o3`
198			`! depth 4, accumulated bits 5`
199			`bl L.4.21`
200			`srl %o5,1,%o5`
201			`! remainder is positive`
202			`subcc %o3,%o5,%o3`
203			`b 9f`
204			`add %o2, (5*2+1), %o2`
205
206			`L.4.21:`
207			`! remainder is negative`
208			`addcc %o3,%o5,%o3`
209			`b 9f`
210			`add %o2, (5*2-1), %o2`
211
212
213
214			`L.2.17:`
215			`! remainder is negative`
216			`addcc %o3,%o5,%o3`
217			`! depth 3, accumulated bits 1`
218			`bl L.3.17`
219			`srl %o5,1,%o5`
220			`! remainder is positive`
221			`subcc %o3,%o5,%o3`
222			`! depth 4, accumulated bits 3`
223			`bl L.4.19`
224			`srl %o5,1,%o5`
225			`! remainder is positive`
226			`subcc %o3,%o5,%o3`
227			`b 9f`
228			`add %o2, (3*2+1), %o2`
229
230			`L.4.19:`
231			`! remainder is negative`
232			`addcc %o3,%o5,%o3`
233			`b 9f`
234			`add %o2, (3*2-1), %o2`
235
236
237			`L.3.17:`
238			`! remainder is negative`
239			`addcc %o3,%o5,%o3`
240			`! depth 4, accumulated bits 1`
241			`bl L.4.17`
242			`srl %o5,1,%o5`
243			`! remainder is positive`
244			`subcc %o3,%o5,%o3`
245			`b 9f`
246			`add %o2, (1*2+1), %o2`
247
248			`L.4.17:`
249			`! remainder is negative`
250			`addcc %o3,%o5,%o3`
251			`b 9f`
252			`add %o2, (1*2-1), %o2`
253
254
255
256
257			`L.1.16:`
258			`! remainder is negative`
259			`addcc %o3,%o5,%o3`
260			`! depth 2, accumulated bits -1`
261			`bl L.2.15`
262			`srl %o5,1,%o5`
263			`! remainder is positive`
264			`subcc %o3,%o5,%o3`
265			`! depth 3, accumulated bits -1`
266			`bl L.3.15`
267			`srl %o5,1,%o5`
268			`! remainder is positive`
269			`subcc %o3,%o5,%o3`
270			`! depth 4, accumulated bits -1`
271			`bl L.4.15`
272			`srl %o5,1,%o5`
273			`! remainder is positive`
274			`subcc %o3,%o5,%o3`
275			`b 9f`
276			`add %o2, (-1*2+1), %o2`
277
278			`L.4.15:`
279			`! remainder is negative`
280			`addcc %o3,%o5,%o3`
281			`b 9f`
282			`add %o2, (-1*2-1), %o2`
283
284
285			`L.3.15:`
286			`! remainder is negative`
287			`addcc %o3,%o5,%o3`
288			`! depth 4, accumulated bits -3`
289			`bl L.4.13`
290			`srl %o5,1,%o5`
291			`! remainder is positive`
292			`subcc %o3,%o5,%o3`
293			`b 9f`
294			`add %o2, (-3*2+1), %o2`
295
296			`L.4.13:`
297			`! remainder is negative`
298			`addcc %o3,%o5,%o3`
299			`b 9f`
300			`add %o2, (-3*2-1), %o2`
301
302
303
304			`L.2.15:`
305			`! remainder is negative`
306			`addcc %o3,%o5,%o3`
307			`! depth 3, accumulated bits -3`
308			`bl L.3.13`
309			`srl %o5,1,%o5`
310			`! remainder is positive`
311			`subcc %o3,%o5,%o3`
312			`! depth 4, accumulated bits -5`
313			`bl L.4.11`
314			`srl %o5,1,%o5`
315			`! remainder is positive`
316			`subcc %o3,%o5,%o3`
317			`b 9f`
318			`add %o2, (-5*2+1), %o2`
319
320			`L.4.11:`
321			`! remainder is negative`
322			`addcc %o3,%o5,%o3`
323			`b 9f`
324			`add %o2, (-5*2-1), %o2`
325
326
327			`L.3.13:`
328			`! remainder is negative`
329			`addcc %o3,%o5,%o3`
330			`! depth 4, accumulated bits -7`
331			`bl L.4.9`
332			`srl %o5,1,%o5`
333			`! remainder is positive`
334			`subcc %o3,%o5,%o3`
335			`b 9f`
336			`add %o2, (-7*2+1), %o2`
337
338			`L.4.9:`
339			`! remainder is negative`
340			`addcc %o3,%o5,%o3`
341			`b 9f`
342			`add %o2, (-7*2-1), %o2`
343
344
345
346
347			`9:`
348			`Lend_regular_divide:`
349			`subcc %o4, 1, %o4`
350			`bge Ldivloop`
351			`tst %o3`
352			`bl,a Lgot_result`
353			`! non-restoring fixup here (one instruction only!)`
354			`add %o3, %o1, %o3`
355
356
357			`Lgot_result:`
358
359			`retl`
360			`mov %o3, %o0`