; ; 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 |vp8_start_encode| EXPORT |vp8_encode_bool| EXPORT |vp8_stop_encode| EXPORT |vp8_encode_value| INCLUDE vpx_vp8_enc_asm_offsets.asm ARM REQUIRE8 PRESERVE8 AREA |.text|, CODE, READONLY ; r0 BOOL_CODER *br ; r1 unsigned char *source |vp8_start_encode| PROC mov r12, #0 mov r3, #255 mvn r2, #23 str r12, [r0, #vp8_writer_lowvalue] str r3, [r0, #vp8_writer_range] str r12, [r0, #vp8_writer_value] str r2, [r0, #vp8_writer_count] str r12, [r0, #vp8_writer_pos] str r1, [r0, #vp8_writer_buffer] bx lr ENDP ; r0 BOOL_CODER *br ; r1 int bit ; r2 int probability |vp8_encode_bool| PROC push {r4-r9, lr} mov r4, r2 ldr r2, [r0, #vp8_writer_lowvalue] ldr r5, [r0, #vp8_writer_range] ldr r3, [r0, #vp8_writer_count] sub r7, r5, #1 ; range-1 cmp r1, #0 mul r4, r4, r7 ; ((range-1) * probability) mov r7, #1 add r4, r7, r4, lsr #8 ; 1 + (((range-1) * probability) >> 8) addne r2, r2, r4 ; if (bit) lowvalue += split subne r4, r5, r4 ; if (bit) 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 r9, #0 strb r9, [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 r1, [r7, r4] cmpge r1, #0xff beq token_zero_while_loop ldr r7, [r0, #vp8_writer_buffer] ldrb r9, [r7, r4] ; w->buffer[x] add r9, r9, #1 strb r9, [r7, r4] ; w->buffer[x] + 1 token_high_bit_not_set rsb r4, r6, #24 ; 24-offset ldr r9, [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 r1, r4, #1 ; w->pos++ bic r2, r2, #0xff000000 ; lowvalue &= 0xffffff str r1, [r0, #vp8_writer_pos] sub r3, r3, #8 ; count -= 8 strb r7, [r9, r4] ; w->buffer[w->pos++] token_count_lt_zero lsl r2, r2, r6 ; lowvalue <<= shift str r2, [r0, #vp8_writer_lowvalue] str r5, [r0, #vp8_writer_range] str r3, [r0, #vp8_writer_count] pop {r4-r9, pc} ENDP ; r0 BOOL_CODER *br |vp8_stop_encode| PROC push {r4-r10, lr} ldr r2, [r0, #vp8_writer_lowvalue] ldr r5, [r0, #vp8_writer_range] ldr r3, [r0, #vp8_writer_count] mov r10, #32 stop_encode_loop sub r7, r5, #1 ; range-1 mov r4, r7, lsl #7 ; ((range-1) * 128) mov r7, #1 add r4, r7, r4, lsr #8 ; 1 + (((range-1) * 128) >> 8) ; 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_se ; 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_se ldr r4, [r0, #vp8_writer_pos] ; x sub r4, r4, #1 ; x = w->pos-1 b token_zero_while_start_se token_zero_while_loop_se mov r9, #0 strb r9, [r7, r4] ; w->buffer[x] =(unsigned char)0 sub r4, r4, #1 ; x-- token_zero_while_start_se cmp r4, #0 ldrge r7, [r0, #vp8_writer_buffer] ldrb r1, [r7, r4] cmpge r1, #0xff beq token_zero_while_loop_se ldr r7, [r0, #vp8_writer_buffer] ldrb r9, [r7, r4] ; w->buffer[x] add r9, r9, #1 strb r9, [r7, r4] ; w->buffer[x] + 1 token_high_bit_not_set_se rsb r4, r6, #24 ; 24-offset ldr r9, [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 r1, r4, #1 ; w->pos++ bic r2, r2, #0xff000000 ; lowvalue &= 0xffffff str r1, [r0, #vp8_writer_pos] sub r3, r3, #8 ; count -= 8 strb r7, [r9, r4] ; w->buffer[w->pos++] token_count_lt_zero_se lsl r2, r2, r6 ; lowvalue <<= shift subs r10, r10, #1 bne stop_encode_loop str r2, [r0, #vp8_writer_lowvalue] str r5, [r0, #vp8_writer_range] str r3, [r0, #vp8_writer_count] pop {r4-r10, pc} ENDP ; r0 BOOL_CODER *br ; r1 int data ; r2 int bits |vp8_encode_value| PROC push {r4-r11, lr} mov r10, r2 ldr r2, [r0, #vp8_writer_lowvalue] ldr r5, [r0, #vp8_writer_range] ldr r3, [r0, #vp8_writer_count] ; 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 r11, r1 rsb r4, r10, #32 ; 32-n ; v is kept in r1 during the token pack loop lsr r1, r11, r4 ; v >>= 32 - n encode_value_loop 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 r1, r1, #1 ; bit = v >> n mov r4, r7, lsl #7 ; ((range-1) * 128) mov r7, #1 add r4, r7, r4, lsr #8 ; 1 + (((range-1) * 128) >> 8) addcs r2, r2, r4 ; if (bit) lowvalue += split subcs r4, r5, r4 ; if (bit) 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_ev ; 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_ev ldr r4, [r0, #vp8_writer_pos] ; x sub r4, r4, #1 ; x = w->pos-1 b token_zero_while_start_ev token_zero_while_loop_ev mov r9, #0 strb r9, [r7, r4] ; w->buffer[x] =(unsigned char)0 sub r4, r4, #1 ; x-- token_zero_while_start_ev cmp r4, #0 ldrge r7, [r0, #vp8_writer_buffer] ldrb r11, [r7, r4] cmpge r11, #0xff beq token_zero_while_loop_ev ldr r7, [r0, #vp8_writer_buffer] ldrb r9, [r7, r4] ; w->buffer[x] add r9, r9, #1 strb r9, [r7, r4] ; w->buffer[x] + 1 token_high_bit_not_set_ev rsb r4, r6, #24 ; 24-offset ldr r9, [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, [r9, r4] ; w->buffer[w->pos++] token_count_lt_zero_ev lsl r2, r2, r6 ; lowvalue <<= shift subs r10, r10, #1 bne encode_value_loop str r2, [r0, #vp8_writer_lowvalue] str r5, [r0, #vp8_writer_range] str r3, [r0, #vp8_writer_count] pop {r4-r11, pc} ENDP END