| ; |
| ; Copyright (c) 2010 The VP8 project authors. All Rights Reserved. |
| ; |
| ; Use of this source code is governed by a BSD-style license and patent |
| ; grant that can be found in the LICENSE file in the root of the source |
| ; tree. All contributing project authors may be found in the AUTHORS |
| ; file in the root of the source tree. |
| ; |
| |
| |
| EXPORT |vp8cx_pack_tokens_armv7| |
| |
| INCLUDE vpx_vp8_enc_asm_offsets.asm |
| |
| ARM |
| REQUIRE8 |
| PRESERVE8 |
| |
| AREA |.text|, CODE, READONLY |
| |
| ; r0 vp8_writer *w |
| ; r1 const TOKENEXTRA *p |
| ; r2 int xcount |
| ; r3 vp8_coef_encodings |
| ; s0 vp8_extra_bits |
| ; s1 vp8_coef_tree |
| |vp8cx_pack_tokens_armv7| PROC |
| push {r4-r11, lr} |
| |
| ; Add size of xcount * sizeof (TOKENEXTRA) to get stop |
| ; sizeof (TOKENEXTRA) is 20 |
| add r2, r2, r2, lsl #2 ; xcount |
| sub sp, sp, #12 |
| add r2, r1, r2, lsl #2 ; stop = p + xcount |
| str r2, [sp, #0] |
| str r3, [sp, #8] ; save vp8_coef_encodings |
| ldr r2, [r0, #vp8_writer_lowvalue] |
| ldr r5, [r0, #vp8_writer_range] |
| ldr r3, [r0, #vp8_writer_count] |
| b check_p_lt_stop |
| |
| while_p_lt_stop |
| ldr r6, [r1, #tokenextra_token] ; t |
| ldr r4, [sp, #8] ; vp8_coef_encodings |
| mov lr, #0 |
| add r4, r4, r6, lsl #3 ; a = vp8_coef_encodings + t |
| ldr r9, [r1, #tokenextra_context_tree] ; pp |
| |
| ldr r7, [r1, #tokenextra_skip_eob_node] |
| |
| ldr r6, [r4, #vp8_token_value] ; v |
| ldr r8, [r4, #vp8_token_len] ; n |
| |
| ; vp8 specific skip_eob_node |
| cmp r7, #0 |
| movne lr, #2 ; i = 2 |
| subne r8, r8, #1 ; --n |
| |
| ; reverse the stream of bits to be packed. Normally |
| ; the most significant bit is peeled off and compared |
| ; in the form of (v >> --n) & 1. ARM architecture has |
| ; the ability to set a flag based on the value of the |
| ; bit shifted off the bottom of the register. To make |
| ; that happen the bitstream is reversed. |
| rbit r12, r6 |
| rsb r4, r8, #32 ; 32-n |
| ldr r10, [sp, #52] ; vp8_coef_tree |
| |
| ; v is kept in r12 during the token pack loop |
| lsr r12, r12, r4 ; v >>= 32 - n |
| |
| ; loop start |
| token_loop |
| ldrb r4, [r9, lr, asr #1] ; pp [i>>1] |
| sub r7, r5, #1 ; range-1 |
| |
| ; Decisions are made based on the bit value shifted |
| ; off of v, so set a flag here based on this. |
| ; This value is refered to as "bb" |
| lsrs r12, r12, #1 ; bb = v >> n |
| mul r4, r4, r7 ; ((range-1) * pp[i>>1])) |
| |
| ; bb can only be 0 or 1. So only execute this statement |
| ; if bb == 1, otherwise it will act like i + 0 |
| addcs lr, lr, #1 ; i + bb |
| |
| mov r7, #1 |
| ldrsb lr, [r10, lr] ; i = vp8_coef_tree[i+bb] |
| add r4, r7, r4, lsr #8 ; 1 + (((range-1) * pp[i>>1]) >> 8) |
| |
| addcs r2, r2, r4 ; if (bb) lowvalue += split |
| subcs r4, r5, r4 ; if (bb) range = range-split |
| |
| ; Counting the leading zeros is used to normalize range. |
| clz r6, r4 |
| sub r6, r6, #24 ; shift |
| |
| ; Flag is set on the sum of count. This flag is used later |
| ; to determine if count >= 0 |
| adds r3, r3, r6 ; count += shift |
| lsl r5, r4, r6 ; range <<= shift |
| bmi token_count_lt_zero ; if(count >= 0) |
| |
| sub r6, r6, r3 ; offset = shift - count |
| sub r4, r6, #1 ; offset-1 |
| lsls r4, r2, r4 ; if((lowvalue<<(offset-1)) & 0x80000000 ) |
| bpl token_high_bit_not_set |
| |
| ldr r4, [r0, #vp8_writer_pos] ; x |
| sub r4, r4, #1 ; x = w->pos-1 |
| b token_zero_while_start |
| token_zero_while_loop |
| mov r10, #0 |
| strb r10, [r7, r4] ; w->buffer[x] =(unsigned char)0 |
| sub r4, r4, #1 ; x-- |
| token_zero_while_start |
| cmp r4, #0 |
| ldrge r7, [r0, #vp8_writer_buffer] |
| ldrb r11, [r7, r4] |
| cmpge r11, #0xff |
| beq token_zero_while_loop |
| |
| ldr r7, [r0, #vp8_writer_buffer] |
| ldrb r10, [r7, r4] ; w->buffer[x] |
| add r10, r10, #1 |
| strb r10, [r7, r4] ; w->buffer[x] + 1 |
| token_high_bit_not_set |
| rsb r4, r6, #24 ; 24-offset |
| ldr r10, [r0, #vp8_writer_buffer] |
| lsr r7, r2, r4 ; lowvalue >> (24-offset) |
| ldr r4, [r0, #vp8_writer_pos] ; w->pos |
| lsl r2, r2, r6 ; lowvalue <<= offset |
| mov r6, r3 ; shift = count |
| add r11, r4, #1 ; w->pos++ |
| bic r2, r2, #0xff000000 ; lowvalue &= 0xffffff |
| str r11, [r0, #vp8_writer_pos] |
| sub r3, r3, #8 ; count -= 8 |
| strb r7, [r10, r4] ; w->buffer[w->pos++] |
| |
| ; r10 is used earlier in the loop, but r10 is used as |
| ; temp variable here. So after r10 is used, reload |
| ; vp8_coef_tree_dcd into r10 |
| ldr r10, [sp, #52] ; vp8_coef_tree |
| |
| token_count_lt_zero |
| lsl r2, r2, r6 ; lowvalue <<= shift |
| |
| subs r8, r8, #1 ; --n |
| bne token_loop |
| |
| ldr r6, [r1, #tokenextra_token] ; t |
| ldr r7, [sp, #48] ; vp8_extra_bits |
| ; Add t * sizeof (vp8_extra_bit_struct) to get the desired |
| ; element. Here vp8_extra_bit_struct == 20 |
| add r6, r6, r6, lsl #2 ; b = vp8_extra_bits + t |
| add r12, r7, r6, lsl #2 ; b = vp8_extra_bits + t |
| |
| ldr r4, [r12, #vp8_extra_bit_struct_base_val] |
| cmp r4, #0 |
| beq skip_extra_bits |
| |
| ; if( b->base_val) |
| ldr r8, [r12, #vp8_extra_bit_struct_len] ; L |
| ldr lr, [r1, #tokenextra_extra] ; e = p->Extra |
| cmp r8, #0 ; if( L) |
| beq no_extra_bits |
| |
| ldr r9, [r12, #vp8_extra_bit_struct_prob] |
| asr r7, lr, #1 ; v=e>>1 |
| |
| ldr r10, [r12, #vp8_extra_bit_struct_tree] |
| str r10, [sp, #4] ; b->tree |
| |
| rbit r12, r7 ; reverse v |
| rsb r4, r8, #32 |
| lsr r12, r12, r4 |
| |
| mov lr, #0 ; i = 0 |
| |
| extra_bits_loop |
| ldrb r4, [r9, lr, asr #1] ; pp[i>>1] |
| sub r7, r5, #1 ; range-1 |
| lsrs r12, r12, #1 ; v >> n |
| mul r4, r4, r7 ; (range-1) * pp[i>>1] |
| addcs lr, lr, #1 ; i + bb |
| |
| mov r7, #1 |
| ldrsb lr, [r10, lr] ; i = b->tree[i+bb] |
| add r4, r7, r4, lsr #8 ; split = 1 + (((range-1) * pp[i>>1]) >> 8) |
| |
| addcs r2, r2, r4 ; if (bb) lowvalue += split |
| subcs r4, r5, r4 ; if (bb) range = range-split |
| |
| clz r6, r4 |
| sub r6, r6, #24 |
| |
| adds r3, r3, r6 ; count += shift |
| lsl r5, r4, r6 ; range <<= shift |
| bmi extra_count_lt_zero ; if(count >= 0) |
| |
| sub r6, r6, r3 ; offset= shift - count |
| sub r4, r6, #1 ; offset-1 |
| lsls r4, r2, r4 ; if((lowvalue<<(offset-1)) & 0x80000000 ) |
| bpl extra_high_bit_not_set |
| |
| ldr r4, [r0, #vp8_writer_pos] ; x |
| sub r4, r4, #1 ; x = w->pos - 1 |
| b extra_zero_while_start |
| extra_zero_while_loop |
| mov r10, #0 |
| strb r10, [r7, r4] ; w->buffer[x] =(unsigned char)0 |
| sub r4, r4, #1 ; x-- |
| extra_zero_while_start |
| cmp r4, #0 |
| ldrge r7, [r0, #vp8_writer_buffer] |
| ldrb r11, [r7, r4] |
| cmpge r11, #0xff |
| beq extra_zero_while_loop |
| |
| ldr r7, [r0, #vp8_writer_buffer] |
| ldrb r10, [r7, r4] |
| add r10, r10, #1 |
| strb r10, [r7, r4] |
| extra_high_bit_not_set |
| rsb r4, r6, #24 ; 24-offset |
| ldr r10, [r0, #vp8_writer_buffer] |
| lsr r7, r2, r4 ; lowvalue >> (24-offset) |
| ldr r4, [r0, #vp8_writer_pos] |
| lsl r2, r2, r6 ; lowvalue <<= offset |
| mov r6, r3 ; shift = count |
| add r11, r4, #1 ; w->pos++ |
| bic r2, r2, #0xff000000 ; lowvalue &= 0xffffff |
| str r11, [r0, #vp8_writer_pos] |
| sub r3, r3, #8 ; count -= 8 |
| strb r7, [r10, r4] ; w->buffer[w->pos++]=(lowvalue >> (24-offset)) |
| ldr r10, [sp, #4] ; b->tree |
| extra_count_lt_zero |
| lsl r2, r2, r6 |
| |
| subs r8, r8, #1 ; --n |
| bne extra_bits_loop ; while (n) |
| |
| no_extra_bits |
| ldr lr, [r1, #4] ; e = p->Extra |
| add r4, r5, #1 ; range + 1 |
| tst lr, #1 |
| lsr r4, r4, #1 ; split = (range + 1) >> 1 |
| addne r2, r2, r4 ; lowvalue += split |
| subne r4, r5, r4 ; range = range-split |
| tst r2, #0x80000000 ; lowvalue & 0x80000000 |
| lsl r5, r4, #1 ; range <<= 1 |
| beq end_high_bit_not_set |
| |
| ldr r4, [r0, #vp8_writer_pos] |
| mov r7, #0 |
| sub r4, r4, #1 |
| b end_zero_while_start |
| end_zero_while_loop |
| strb r7, [r6, r4] |
| sub r4, r4, #1 ; x-- |
| end_zero_while_start |
| cmp r4, #0 |
| ldrge r6, [r0, #vp8_writer_buffer] |
| ldrb r12, [r6, r4] |
| cmpge r12, #0xff |
| beq end_zero_while_loop |
| |
| ldr r6, [r0, #vp8_writer_buffer] |
| ldrb r7, [r6, r4] |
| add r7, r7, #1 |
| strb r7, [r6, r4] |
| end_high_bit_not_set |
| adds r3, r3, #1 ; ++count |
| lsl r2, r2, #1 ; lowvalue <<= 1 |
| bne end_count_zero |
| |
| ldr r4, [r0, #vp8_writer_pos] |
| mvn r3, #7 |
| ldr r7, [r0, #vp8_writer_buffer] |
| lsr r6, r2, #24 ; lowvalue >> 24 |
| add r12, r4, #1 ; w->pos++ |
| bic r2, r2, #0xff000000 ; lowvalue &= 0xffffff |
| str r12, [r0, #0x10] |
| strb r6, [r7, r4] |
| end_count_zero |
| skip_extra_bits |
| add r1, r1, #TOKENEXTRA_SZ ; ++p |
| check_p_lt_stop |
| ldr r4, [sp, #0] ; stop |
| cmp r1, r4 ; while( p < stop) |
| bcc while_p_lt_stop |
| |
| str r2, [r0, #vp8_writer_lowvalue] |
| str r5, [r0, #vp8_writer_range] |
| str r3, [r0, #vp8_writer_count] |
| add sp, sp, #12 |
| pop {r4-r11, pc} |
| ENDP |
| |
| END |
