; ; 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