| ;// |
| ;// |
| ;// File Name: armVCM4P10_UnpackBlock4x4_s.s |
| ;// OpenMAX DL: v1.0.2 |
| ;// Revision: 12290 |
| ;// Date: Wednesday, April 9, 2008 |
| ;// |
| ;// (c) Copyright 2007-2008 ARM Limited. All Rights Reserved. |
| ;// |
| ;// |
| ;// |
| |
| |
| INCLUDE omxtypes_s.h |
| INCLUDE armCOMM_s.h |
| |
| ;// Define the processor variants supported by this file |
| |
| M_VARIANTS ARM1136JS |
| |
| |
| IF ARM1136JS |
| |
| ;//-------------------------------------- |
| ;// Input Arguments and their scope/usage |
| ;//-------------------------------------- |
| ppSrc RN 0 ;// Persistent variable |
| pDst RN 1 ;// Persistent variable |
| |
| ;//-------------------------------- |
| ;// Variables and their scope/usage |
| ;//-------------------------------- |
| pSrc RN 2 ;// Persistent variables |
| Flag RN 3 |
| Value RN 4 |
| Value2 RN 5 |
| strOffset RN 6 |
| cstOffset RN 7 |
| |
| |
| M_START armVCM4P10_UnpackBlock4x4, r7 |
| |
| LDR pSrc, [ppSrc] ;// Load pSrc |
| MOV cstOffset, #31 ;// To be used in the loop, to compute offset |
| |
| ;//----------------------------------------------------------------------- |
| ; Firstly, fill all the coefficient values on the <pDst> buffer by zero |
| ;//----------------------------------------------------------------------- |
| |
| MOV Value, #0 ;// Initialize the zero value |
| MOV Value2, #0 ;// Initialize the zero value |
| LDRB Flag, [pSrc], #1 ;// Preload <Flag> before <unpackLoop> |
| |
| STRD Value, [pDst, #0] ;// pDst[0] = pDst[1] = pDst[2] = pDst[3] = 0 |
| STRD Value, [pDst, #8] ;// pDst[4] = pDst[5] = pDst[6] = pDst[7] = 0 |
| STRD Value, [pDst, #16] ;// pDst[8] = pDst[9] = pDst[10] = pDst[11] = 0 |
| STRD Value, [pDst, #24] ;// pDst[12] = pDst[13] = pDst[14] = pDst[15] = 0 |
| |
| ;//---------------------------------------------------------------------------- |
| ;// The loop below parses and unpacks the input stream. The C-model has |
| ;// a somewhat complicated logic for sign extension. But in the v6 version, |
| ;// that can be easily taken care by loading the data from <pSrc> stream as |
| ;// SIGNED byte/halfword. So, based on the first TST instruction, 8-bits or |
| ;// 16-bits are read. |
| ;// |
| ;// Next, to compute the offset, where the unpacked value needs to be stored, |
| ;// we modify the computation to perform [(Flag & 15) < 1] as [(Flag < 1) & 31] |
| ;// This results in a saving of one cycle. |
| ;//---------------------------------------------------------------------------- |
| |
| unpackLoop |
| TST Flag, #0x10 ;// Computing (Flag & 0x10) |
| LDRSBNE Value2,[pSrc,#1] ;// Load byte wise to avoid unaligned access |
| LDRBNE Value, [pSrc], #2 |
| AND strOffset, cstOffset, Flag, LSL #1 ;// strOffset = (Flag & 15) < 1; |
| LDRSBEQ Value, [pSrc], #1 ;// Value = (OMX_U8) *pSrc++ |
| ORRNE Value,Value,Value2, LSL #8 ;// Value = (OMX_U16) *pSrc++ |
| |
| TST Flag, #0x20 ;// Computing (Flag & 0x20) to check, if we're done |
| LDRBEQ Flag, [pSrc], #1 ;// Flag = (OMX_U8) *pSrc++, for next iteration |
| STRH Value, [pDst, strOffset] ;// Store <Value> at offset <strOffset> |
| BEQ unpackLoop ;// Branch to the loop beginning |
| |
| STR pSrc, [ppSrc] ;// Update the bitstream pointer |
| M_END |
| |
| ENDIF |
| |
| |
| |
| END |
| |
