1/*
2   C-like prototype :
3        void j_rev_dct_arm(DCTBLOCK data)
4
5   With DCTBLOCK being a pointer to an array of 64 'signed shorts'
6
7   Copyright (c) 2001 Lionel Ulmer (lionel.ulmer@free.fr / bbrox@bbrox.org)
8
9   Permission is hereby granted, free of charge, to any person obtaining a copy
10   of this software and associated documentation files (the "Software"), to deal
11   in the Software without restriction, including without limitation the rights
12   to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
13   copies of the Software, and to permit persons to whom the Software is
14   furnished to do so, subject to the following conditions:
15
16   The above copyright notice and this permission notice shall be included in
17   all copies or substantial portions of the Software.
18
19   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
20   IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
21   FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
22   COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
23   IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
24   CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
25
26*/
27
28#include "asm.S"
29
30#define FIX_0_298631336 2446
31#define FIX_0_541196100 4433
32#define FIX_0_765366865 6270
33#define FIX_1_175875602 9633
34#define FIX_1_501321110 12299
35#define FIX_2_053119869 16819
36#define FIX_3_072711026 25172
37#define FIX_M_0_390180644 -3196
38#define FIX_M_0_899976223 -7373
39#define FIX_M_1_847759065 -15137
40#define FIX_M_1_961570560 -16069
41#define FIX_M_2_562915447 -20995
42#define FIX_0xFFFF 0xFFFF
43
44#define FIX_0_298631336_ID      0
45#define FIX_0_541196100_ID      4
46#define FIX_0_765366865_ID      8
47#define FIX_1_175875602_ID     12
48#define FIX_1_501321110_ID     16
49#define FIX_2_053119869_ID     20
50#define FIX_3_072711026_ID     24
51#define FIX_M_0_390180644_ID   28
52#define FIX_M_0_899976223_ID   32
53#define FIX_M_1_847759065_ID   36
54#define FIX_M_1_961570560_ID   40
55#define FIX_M_2_562915447_ID   44
56#define FIX_0xFFFF_ID          48
57
58function ff_j_rev_dct_arm, export=1
59        push {r0, r4 - r11, lr}
60
61        mov lr, r0                      @ lr = pointer to the current row
62        mov r12, #8                     @ r12 = row-counter
63        movrel r11, const_array         @ r11 = base pointer to the constants array
64row_loop:
65        ldrsh r0, [lr, # 0]             @ r0 = 'd0'
66        ldrsh r2, [lr, # 2]             @ r2 = 'd2'
67
68        @ Optimization for row that have all items except the first set to 0
69        @ (this works as the DCTELEMS are always 4-byte aligned)
70        ldr r5, [lr, # 0]
71        ldr r6, [lr, # 4]
72        ldr r3, [lr, # 8]
73        ldr r4, [lr, #12]
74        orr r3, r3, r4
75        orr r3, r3, r6
76        orrs r5, r3, r5
77        beq end_of_row_loop             @ nothing to be done as ALL of them are '0'
78        orrs r3, r3, r2
79        beq empty_row
80
81        ldrsh r1, [lr, # 8]             @ r1 = 'd1'
82        ldrsh r4, [lr, # 4]             @ r4 = 'd4'
83        ldrsh r6, [lr, # 6]             @ r6 = 'd6'
84
85        ldr r3, [r11, #FIX_0_541196100_ID]
86        add r7, r2, r6
87        ldr r5, [r11, #FIX_M_1_847759065_ID]
88        mul r7, r3, r7                      @ r7 = z1
89        ldr r3, [r11, #FIX_0_765366865_ID]
90        mla r6, r5, r6, r7                  @ r6 = tmp2
91        add r5, r0, r4                      @ r5 = tmp0
92        mla r2, r3, r2, r7                  @ r2 = tmp3
93        sub r3, r0, r4                      @ r3 = tmp1
94
95        add r0, r2, r5, lsl #13             @ r0 = tmp10
96        rsb r2, r2, r5, lsl #13             @ r2 = tmp13
97        add r4, r6, r3, lsl #13             @ r4 = tmp11
98        rsb r3, r6, r3, lsl #13             @ r3 = tmp12
99
100        push {r0, r2, r3, r4} @ save on the stack tmp10, tmp13, tmp12, tmp11
101
102        ldrsh r3, [lr, #10]             @ r3 = 'd3'
103        ldrsh r5, [lr, #12]             @ r5 = 'd5'
104        ldrsh r7, [lr, #14]             @ r7 = 'd7'
105
106        add r0, r3, r5                        @ r0 = 'z2'
107        add r2, r1, r7                  @ r2 = 'z1'
108        add r4, r3, r7                  @ r4 = 'z3'
109        add r6, r1, r5                  @ r6 = 'z4'
110        ldr r9, [r11, #FIX_1_175875602_ID]
111        add r8, r4, r6                  @ r8 = z3 + z4
112        ldr r10, [r11, #FIX_M_0_899976223_ID]
113        mul r8, r9, r8                  @ r8 = 'z5'
114        ldr r9, [r11, #FIX_M_2_562915447_ID]
115        mul r2, r10, r2                 @ r2 = 'z1'
116        ldr r10, [r11, #FIX_M_1_961570560_ID]
117        mul r0, r9, r0                  @ r0 = 'z2'
118        ldr r9, [r11, #FIX_M_0_390180644_ID]
119        mla r4, r10, r4, r8             @ r4 = 'z3'
120        ldr r10, [r11, #FIX_0_298631336_ID]
121        mla r6, r9, r6, r8              @ r6 = 'z4'
122        ldr r9, [r11, #FIX_2_053119869_ID]
123        mla r7, r10, r7, r2             @ r7 = tmp0 + z1
124        ldr r10, [r11, #FIX_3_072711026_ID]
125        mla r5, r9, r5, r0              @ r5 = tmp1 + z2
126        ldr r9, [r11, #FIX_1_501321110_ID]
127        mla r3, r10, r3, r0             @ r3 = tmp2 + z2
128        add r7, r7, r4                  @ r7 = tmp0
129        mla r1, r9, r1, r2              @ r1 = tmp3 + z1
130        add r5,        r5, r6                  @ r5 = tmp1
131        add r3, r3, r4                  @ r3 = tmp2
132        add r1, r1, r6                  @ r1 = tmp3
133
134        pop {r0, r2, r4, r6} @ r0 = tmp10 / r2 = tmp13 / r4 = tmp12 / r6 = tmp11
135                             @ r1 = tmp3  / r3 = tmp2  / r5 = tmp1  / r7 = tmp0
136
137        @ Compute DESCALE(tmp10 + tmp3, CONST_BITS-PASS1_BITS)
138        add r8, r0, r1
139        add r8, r8, #(1<<10)
140        mov r8, r8, asr #11
141        strh r8, [lr, # 0]
142
143        @ Compute DESCALE(tmp10 - tmp3, CONST_BITS-PASS1_BITS)
144        sub r8, r0, r1
145        add r8, r8, #(1<<10)
146        mov r8, r8, asr #11
147        strh r8, [lr, #14]
148
149        @ Compute DESCALE(tmp11 + tmp2, CONST_BITS-PASS1_BITS)
150        add r8, r6, r3
151        add r8, r8, #(1<<10)
152        mov r8, r8, asr #11
153        strh r8, [lr, # 2]
154
155        @ Compute DESCALE(tmp11 - tmp2, CONST_BITS-PASS1_BITS)
156        sub r8, r6, r3
157        add r8, r8, #(1<<10)
158        mov r8, r8, asr #11
159        strh r8, [lr, #12]
160
161        @ Compute DESCALE(tmp12 + tmp1, CONST_BITS-PASS1_BITS)
162        add r8, r4, r5
163        add r8, r8, #(1<<10)
164        mov r8, r8, asr #11
165        strh r8, [lr, # 4]
166
167        @ Compute DESCALE(tmp12 - tmp1, CONST_BITS-PASS1_BITS)
168        sub r8, r4, r5
169        add r8, r8, #(1<<10)
170        mov r8, r8, asr #11
171        strh r8, [lr, #10]
172
173        @ Compute DESCALE(tmp13 + tmp0, CONST_BITS-PASS1_BITS)
174        add r8, r2, r7
175        add r8, r8, #(1<<10)
176        mov r8, r8, asr #11
177        strh r8, [lr, # 6]
178
179        @ Compute DESCALE(tmp13 - tmp0, CONST_BITS-PASS1_BITS)
180        sub r8, r2, r7
181        add r8, r8, #(1<<10)
182        mov r8, r8, asr #11
183        strh r8, [lr, # 8]
184
185        @ End of row loop
186        add lr, lr, #16
187        subs r12, r12, #1
188        bne row_loop
189        beq start_column_loop
190
191empty_row:
192        ldr r1, [r11, #FIX_0xFFFF_ID]
193        mov r0, r0, lsl #2
194        and r0, r0, r1
195        add r0, r0, r0, lsl #16
196        str r0, [lr, # 0]
197        str r0, [lr, # 4]
198        str r0, [lr, # 8]
199        str r0, [lr, #12]
200
201end_of_row_loop:
202        @ End of loop
203        add lr, lr, #16
204        subs r12, r12, #1
205        bne row_loop
206
207start_column_loop:
208        @ Start of column loop
209        pop {lr}
210        mov r12, #8
211column_loop:
212        ldrsh r0, [lr, #( 0*8)]             @ r0 = 'd0'
213        ldrsh r2, [lr, #( 4*8)]             @ r2 = 'd2'
214        ldrsh r4, [lr, #( 8*8)]             @ r4 = 'd4'
215        ldrsh r6, [lr, #(12*8)]             @ r6 = 'd6'
216
217        ldr r3, [r11, #FIX_0_541196100_ID]
218        add r1, r2, r6
219        ldr r5, [r11, #FIX_M_1_847759065_ID]
220        mul r1, r3, r1                      @ r1 = z1
221        ldr r3, [r11, #FIX_0_765366865_ID]
222        mla r6, r5, r6, r1                  @ r6 = tmp2
223        add r5, r0, r4                      @ r5 = tmp0
224        mla r2, r3, r2, r1                  @ r2 = tmp3
225        sub r3, r0, r4                      @ r3 = tmp1
226
227        add r0, r2, r5, lsl #13             @ r0 = tmp10
228        rsb r2, r2, r5, lsl #13             @ r2 = tmp13
229        add r4, r6, r3, lsl #13             @ r4 = tmp11
230        rsb r6, r6, r3, lsl #13             @ r6 = tmp12
231
232        ldrsh r1, [lr, #( 2*8)]             @ r1 = 'd1'
233        ldrsh r3, [lr, #( 6*8)]             @ r3 = 'd3'
234        ldrsh r5, [lr, #(10*8)]             @ r5 = 'd5'
235        ldrsh r7, [lr, #(14*8)]             @ r7 = 'd7'
236
237        @ Check for empty odd column (happens about 20 to 25 % of the time according to my stats)
238        orr r9, r1, r3
239        orr r10, r5, r7
240        orrs r10, r9, r10
241        beq empty_odd_column
242
243        push {r0, r2, r4, r6} @ save on the stack tmp10, tmp13, tmp12, tmp11
244
245        add r0, r3, r5                  @ r0 = 'z2'
246        add r2, r1, r7                  @ r2 = 'z1'
247        add r4, r3, r7                  @ r4 = 'z3'
248        add r6, r1, r5                  @ r6 = 'z4'
249        ldr r9, [r11, #FIX_1_175875602_ID]
250        add r8, r4, r6
251        ldr r10, [r11, #FIX_M_0_899976223_ID]
252        mul r8, r9, r8                  @ r8 = 'z5'
253        ldr r9, [r11, #FIX_M_2_562915447_ID]
254        mul r2, r10, r2                 @ r2 = 'z1'
255        ldr r10, [r11, #FIX_M_1_961570560_ID]
256        mul r0, r9, r0                  @ r0 = 'z2'
257        ldr r9, [r11, #FIX_M_0_390180644_ID]
258        mla r4, r10, r4, r8             @ r4 = 'z3'
259        ldr r10, [r11, #FIX_0_298631336_ID]
260        mla r6, r9, r6, r8              @ r6 = 'z4'
261        ldr r9, [r11, #FIX_2_053119869_ID]
262        mla r7, r10, r7, r2             @ r7 = tmp0 + z1
263        ldr r10, [r11, #FIX_3_072711026_ID]
264        mla r5, r9, r5, r0              @ r5 = tmp1 + z2
265        ldr r9, [r11, #FIX_1_501321110_ID]
266        mla r3, r10, r3, r0             @ r3 = tmp2 + z2
267        add r7, r7, r4                  @ r7 = tmp0
268        mla r1, r9, r1, r2              @ r1 = tmp3 + z1
269        add r5,        r5, r6                  @ r5 = tmp1
270        add r3, r3, r4                  @ r3 = tmp2
271        add r1, r1, r6                  @ r1 = tmp3
272
273        pop {r0, r2, r4, r6} @ r0 = tmp10 / r2 = tmp13 / r4 = tmp11 / r6 = tmp12
274                             @ r1 = tmp3  / r3 = tmp2  / r5 = tmp1  / r7 = tmp0
275
276        @ Compute DESCALE(tmp10 + tmp3, CONST_BITS+PASS1_BITS+3)
277        add r8, r0, r1
278        add r8, r8, #(1<<17)
279        mov r8, r8, asr #18
280        strh r8, [lr, #( 0*8)]
281
282        @ Compute DESCALE(tmp10 - tmp3, CONST_BITS+PASS1_BITS+3)
283        sub r8, r0, r1
284        add r8, r8, #(1<<17)
285        mov r8, r8, asr #18
286        strh r8, [lr, #(14*8)]
287
288        @ Compute DESCALE(tmp11 + tmp2, CONST_BITS+PASS1_BITS+3)
289        add r8, r4, r3
290        add r8, r8, #(1<<17)
291        mov r8, r8, asr #18
292        strh r8, [lr, #( 2*8)]
293
294        @ Compute DESCALE(tmp11 - tmp2, CONST_BITS+PASS1_BITS+3)
295        sub r8, r4, r3
296        add r8, r8, #(1<<17)
297        mov r8, r8, asr #18
298        strh r8, [lr, #(12*8)]
299
300        @ Compute DESCALE(tmp12 + tmp1, CONST_BITS+PASS1_BITS+3)
301        add r8, r6, r5
302        add r8, r8, #(1<<17)
303        mov r8, r8, asr #18
304        strh r8, [lr, #( 4*8)]
305
306        @ Compute DESCALE(tmp12 - tmp1, CONST_BITS+PASS1_BITS+3)
307        sub r8, r6, r5
308        add r8, r8, #(1<<17)
309        mov r8, r8, asr #18
310        strh r8, [lr, #(10*8)]
311
312        @ Compute DESCALE(tmp13 + tmp0, CONST_BITS+PASS1_BITS+3)
313        add r8, r2, r7
314        add r8, r8, #(1<<17)
315        mov r8, r8, asr #18
316        strh r8, [lr, #( 6*8)]
317
318        @ Compute DESCALE(tmp13 - tmp0, CONST_BITS+PASS1_BITS+3)
319        sub r8, r2, r7
320        add r8, r8, #(1<<17)
321        mov r8, r8, asr #18
322        strh r8, [lr, #( 8*8)]
323
324        @ End of row loop
325        add lr, lr, #2
326        subs r12, r12, #1
327        bne column_loop
328        beq the_end
329
330empty_odd_column:
331        @ Compute DESCALE(tmp10 + tmp3, CONST_BITS+PASS1_BITS+3)
332        @ Compute DESCALE(tmp10 - tmp3, CONST_BITS+PASS1_BITS+3)
333        add r0, r0, #(1<<17)
334        mov r0, r0, asr #18
335        strh r0, [lr, #( 0*8)]
336        strh r0, [lr, #(14*8)]
337
338        @ Compute DESCALE(tmp11 + tmp2, CONST_BITS+PASS1_BITS+3)
339        @ Compute DESCALE(tmp11 - tmp2, CONST_BITS+PASS1_BITS+3)
340        add r4, r4, #(1<<17)
341        mov r4, r4, asr #18
342        strh r4, [lr, #( 2*8)]
343        strh r4, [lr, #(12*8)]
344
345        @ Compute DESCALE(tmp12 + tmp1, CONST_BITS+PASS1_BITS+3)
346        @ Compute DESCALE(tmp12 - tmp1, CONST_BITS+PASS1_BITS+3)
347        add r6, r6, #(1<<17)
348        mov r6, r6, asr #18
349        strh r6, [lr, #( 4*8)]
350        strh r6, [lr, #(10*8)]
351
352        @ Compute DESCALE(tmp13 + tmp0, CONST_BITS+PASS1_BITS+3)
353        @ Compute DESCALE(tmp13 - tmp0, CONST_BITS+PASS1_BITS+3)
354        add r2, r2, #(1<<17)
355        mov r2, r2, asr #18
356        strh r2, [lr, #( 6*8)]
357        strh r2, [lr, #( 8*8)]
358
359        @ End of row loop
360        add lr, lr, #2
361        subs r12, r12, #1
362        bne column_loop
363
364the_end:
365        @ The end....
366        pop {r4 - r11, pc}
367endfunc
368
369const const_array
370        .word FIX_0_298631336
371        .word FIX_0_541196100
372        .word FIX_0_765366865
373        .word FIX_1_175875602
374        .word FIX_1_501321110
375        .word FIX_2_053119869
376        .word FIX_3_072711026
377        .word FIX_M_0_390180644
378        .word FIX_M_0_899976223
379        .word FIX_M_1_847759065
380        .word FIX_M_1_961570560
381        .word FIX_M_2_562915447
382        .word FIX_0xFFFF
383endconst
384