rockbox/apps/codecs/libtremor/asm_arm.h

/********************************************************************
 *                                                                  *
 * THIS FILE IS PART OF THE OggVorbis 'TREMOR' CODEC SOURCE CODE.   *
 *                                                                  *
 * USE, DISTRIBUTION AND REPRODUCTION OF THIS LIBRARY SOURCE IS     *
 * GOVERNED BY A BSD-STYLE SOURCE LICENSE INCLUDED WITH THIS SOURCE *
 * IN 'COPYING'. PLEASE READ THESE TERMS BEFORE DISTRIBUTING.       *
 *                                                                  *
 * THE OggVorbis 'TREMOR' SOURCE CODE IS (C) COPYRIGHT 1994-2002    *
 * BY THE Xiph.Org FOUNDATION http://www.xiph.org/                  *
 *                                                                  *
 ********************************************************************

 function: arm7 and later wide math functions

 ********************************************************************/

#ifdef _ARM_ASSEM_

#ifndef _V_LSP_MATH_ASM
#define _V_LSP_MATH_ASM

static inline void lsp_loop_asm(ogg_uint32_t *qip,ogg_uint32_t *pip,
                                ogg_int32_t *qexpp,
                                ogg_int32_t *ilsp,ogg_int32_t wi,
                                ogg_int32_t m){
  
  ogg_uint32_t qi=*qip,pi=*pip;
  ogg_int32_t qexp=*qexpp;

  asm("mov     r0,%3;"
      "movs    r1,%5,asr#1;"
      "add     r0,r0,r1,lsl#3;"
      "beq 2f;\n"
      "1:"
      
      "ldmdb   r0!,{r1,r3};"
      "subs    r1,r1,%4;"          //ilsp[j]-wi
      "rsbmi   r1,r1,#0;"          //labs(ilsp[j]-wi)
      "umull   %0,r2,r1,%0;"       //qi*=labs(ilsp[j]-wi)
      
      "subs    r1,r3,%4;"          //ilsp[j+1]-wi
      "rsbmi   r1,r1,#0;"          //labs(ilsp[j+1]-wi)
      "umull   %1,r3,r1,%1;"       //pi*=labs(ilsp[j+1]-wi)
      
      "cmn     r2,r3;"             // shift down 16?
      "beq     0f;"
      "add     %2,%2,#16;"
      "mov     %0,%0,lsr #16;"
      "orr     %0,%0,r2,lsl #16;"
      "mov     %1,%1,lsr #16;"
      "orr     %1,%1,r3,lsl #16;"
      "0:"
      "cmp     r0,%3;\n"
      "bhi     1b;\n"
      
      "2:"
      // odd filter assymetry
      "ands    r0,%5,#1;\n"
      "beq     3f;\n"
      "add     r0,%3,%5,lsl#2;\n"
      
      "ldr     r1,[r0,#-4];\n"
      "mov     r0,#0x4000;\n"
      
      "subs    r1,r1,%4;\n"          //ilsp[j]-wi
      "rsbmi   r1,r1,#0;\n"          //labs(ilsp[j]-wi)
      "umull   %0,r2,r1,%0;\n"       //qi*=labs(ilsp[j]-wi)
      "umull   %1,r3,r0,%1;\n"       //pi*=labs(ilsp[j+1]-wi)
      
      "cmn     r2,r3;\n"             // shift down 16?
      "beq     3f;\n"
      "add     %2,%2,#16;\n"
      "mov     %0,%0,lsr #16;\n"
      "orr     %0,%0,r2,lsl #16;\n"
      "mov     %1,%1,lsr #16;\n"
      "orr     %1,%1,r3,lsl #16;\n"
      
      //qi=(pi>>shift)*labs(ilsp[j]-wi);
      //pi=(qi>>shift)*labs(ilsp[j+1]-wi);
      //qexp+=shift;

      //}

      /* normalize to max 16 sig figs */
      "3:"
      "mov     r2,#0;"
      "orr     r1,%0,%1;"
      "tst     r1,#0xff000000;"
      "addne   r2,r2,#8;"
      "movne   r1,r1,lsr #8;"
      "tst     r1,#0x00f00000;"
      "addne   r2,r2,#4;"
      "movne   r1,r1,lsr #4;"
      "tst     r1,#0x000c0000;"
      "addne   r2,r2,#2;"
      "movne   r1,r1,lsr #2;"
      "tst     r1,#0x00020000;"
      "addne   r2,r2,#1;"
      "movne   r1,r1,lsr #1;"
      "tst     r1,#0x00010000;"
      "addne   r2,r2,#1;"
      "mov     %0,%0,lsr r2;"
      "mov     %1,%1,lsr r2;"
      "add     %2,%2,r2;"
      
      : "+r"(qi),"+r"(pi),"+r"(qexp)
      : "r"(ilsp),"r"(wi),"r"(m)
      : "r0","r1","r2","r3","cc");
  
  *qip=qi;
  *pip=pi;
  *qexpp=qexp;
}

static inline void lsp_norm_asm(ogg_uint32_t *qip,ogg_int32_t *qexpp){

  ogg_uint32_t qi=*qip;
  ogg_int32_t qexp=*qexpp;

  asm("tst     %0,#0x0000ff00;"
      "moveq   %0,%0,lsl #8;"
      "subeq   %1,%1,#8;"
      "tst     %0,#0x0000f000;"
      "moveq   %0,%0,lsl #4;"
      "subeq   %1,%1,#4;"
      "tst     %0,#0x0000c000;"
      "moveq   %0,%0,lsl #2;"
      "subeq   %1,%1,#2;"
      "tst     %0,#0x00008000;"
      "moveq   %0,%0,lsl #1;"
      "subeq   %1,%1,#1;"
      : "+r"(qi),"+r"(qexp)
      :
      : "cc");
  *qip=qi;
  *qexpp=qexp;
}

#endif
#endif