ref: 17f7f6be4e1a316c0f5f26ff70e047aece4de2bc
dir: /sys/src/cmd/audio/mp3dec/fixed.h/
/* * libmad - MPEG audio decoder library * Copyright (C) 2000-2004 Underbit Technologies, Inc. * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA * * $Id: fixed.h,v 1.38 2004/02/17 02:02:03 rob Exp $ */ # ifndef LIBMAD_FIXED_H # define LIBMAD_FIXED_H typedef int mad_fixed_t; // must be 32 bits typedef int mad_fixed64hi_t; // must be 32 bits typedef u32int mad_fixed64lo_t; // must be 32 bits typedef vlong mad_fixed64_t; # if defined(FPM_FLOAT) typedef double mad_sample_t; # else typedef mad_fixed_t mad_sample_t; # endif /* * Fixed-point format: 0xABBBBBBB * A == whole part (sign + 3 bits) * B == fractional part (28 bits) * * Values are signed two's complement, so the effective range is: * 0x80000000 to 0x7fffffff * -8.0 to +7.9999999962747097015380859375 * * The smallest representable value is: * 0x00000001 == 0.0000000037252902984619140625 (i.e. about 3.725e-9) * * 28 bits of fractional accuracy represent about * 8.6 digits of decimal accuracy. * * Fixed-point numbers can be added or subtracted as normal * integers, but multiplication requires shifting the 64-bit result * from 56 fractional bits back to 28 (and rounding.) * * Changing the definition of MAD_F_FRACBITS is only partially * supported, and must be done with care. */ # define MAD_F_FRACBITS 28 # define MAD_F(x) ((mad_fixed_t) (x)) # define MAD_F_MIN ((mad_fixed_t) -0x80000000L) # define MAD_F_MAX ((mad_fixed_t) +0x7fffffffL) # define MAD_F_ONE MAD_F(0x10000000) # define mad_f_tofixed(x) ((mad_fixed_t) \ ((x) * (double) (1L << MAD_F_FRACBITS) + 0.5)) # define mad_f_todouble(x) ((double) \ ((x) / (double) (1L << MAD_F_FRACBITS))) # define mad_f_intpart(x) ((x) >> MAD_F_FRACBITS) # define mad_f_fracpart(x) ((x) & ((1L << MAD_F_FRACBITS) - 1)) /* (x should be positive) */ # define mad_f_fromint(x) ((x) << MAD_F_FRACBITS) # define mad_f_add(x, y) ((x) + (y)) # define mad_f_sub(x, y) ((x) - (y)) # if defined(FPM_FLOAT) # error "FPM_FLOAT not yet supported" # undef MAD_F # define MAD_F(x) mad_f_todouble(x) # define mad_f_mul(x, y) ((x) * (y)) # define mad_f_scale64 # undef ASO_ZEROCHECK # elif defined(FPM_64BIT) /* * This version should be the most accurate if 64-bit types are supported by * the compiler, although it may not be the most efficient. */ # if defined(OPT_ACCURACY) # define mad_f_mul(x, y) \ ((mad_fixed_t) \ ((((mad_fixed64_t) (x) * (y)) + \ (1L << (MAD_F_SCALEBITS - 1))) >> MAD_F_SCALEBITS)) # else # define mad_f_mul(x, y) \ ((mad_fixed_t) (((mad_fixed64_t) (x) * (y)) >> MAD_F_SCALEBITS)) # endif # define MAD_F_SCALEBITS MAD_F_FRACBITS /* --- Intel --------------------------------------------------------------- */ # elif defined(FPM_INTEL) # if defined(_MSC_VER) # pragma warning(push) # pragma warning(disable: 4035) /* no return value */ static __forceinline mad_fixed_t mad_f_mul_inline(mad_fixed_t x, mad_fixed_t y) { enum { fracbits = MAD_F_FRACBITS }; __asm { mov eax, x imul y shrd eax, edx, fracbits } /* implicit return of eax */ } # pragma warning(pop) # define mad_f_mul mad_f_mul_inline # define mad_f_scale64 # else /* * This Intel version is fast and accurate; the disposition of the least * significant bit depends on OPT_ACCURACY via mad_f_scale64(). */ # define MAD_F_MLX(hi, lo, x, y) \ asm ("imull %3" \ : "=a" (lo), "=d" (hi) \ : "%a" (x), "rm" (y) \ : "cc") # if defined(OPT_ACCURACY) /* * This gives best accuracy but is not very fast. */ # define MAD_F_MLA(hi, lo, x, y) \ ({ mad_fixed64hi_t __hi; \ mad_fixed64lo_t __lo; \ MAD_F_MLX(__hi, __lo, (x), (y)); \ asm ("addl %2,%0\n\t" \ "adcl %3,%1" \ : "=rm" (lo), "=rm" (hi) \ : "r" (__lo), "r" (__hi), "0" (lo), "1" (hi) \ : "cc"); \ }) # endif /* OPT_ACCURACY */ # if defined(OPT_ACCURACY) /* * Surprisingly, this is faster than SHRD followed by ADC. */ # define mad_f_scale64(hi, lo) \ ({ mad_fixed64hi_t __hi_; \ mad_fixed64lo_t __lo_; \ mad_fixed_t __result; \ asm ("addl %4,%2\n\t" \ "adcl %5,%3" \ : "=rm" (__lo_), "=rm" (__hi_) \ : "0" (lo), "1" (hi), \ "ir" (1L << (MAD_F_SCALEBITS - 1)), "ir" (0) \ : "cc"); \ asm ("shrdl %3,%2,%1" \ : "=rm" (__result) \ : "0" (__lo_), "r" (__hi_), "I" (MAD_F_SCALEBITS) \ : "cc"); \ __result; \ }) # elif defined(OPT_INTEL) /* * Alternate Intel scaling that may or may not perform better. */ # define mad_f_scale64(hi, lo) \ ({ mad_fixed_t __result; \ asm ("shrl %3,%1\n\t" \ "shll %4,%2\n\t" \ "orl %2,%1" \ : "=rm" (__result) \ : "0" (lo), "r" (hi), \ "I" (MAD_F_SCALEBITS), "I" (32 - MAD_F_SCALEBITS) \ : "cc"); \ __result; \ }) # else # define mad_f_scale64(hi, lo) \ ({ mad_fixed_t __result; \ asm ("shrdl %3,%2,%1" \ : "=rm" (__result) \ : "0" (lo), "r" (hi), "I" (MAD_F_SCALEBITS) \ : "cc"); \ __result; \ }) # endif /* OPT_ACCURACY */ # define MAD_F_SCALEBITS MAD_F_FRACBITS # endif /* --- ARM ----------------------------------------------------------------- */ # elif defined(FPM_ARM) /* * This ARM V4 version is as accurate as FPM_64BIT but much faster. The * least significant bit is properly rounded at no CPU cycle cost! */ # if 1 /* * This is faster than the default implementation via MAD_F_MLX() and * mad_f_scale64(). */ # define mad_f_mul(x, y) \ ({ mad_fixed64hi_t __hi; \ mad_fixed64lo_t __lo; \ mad_fixed_t __result; \ asm ("smull %0, %1, %3, %4\n\t" \ "movs %0, %0, lsr %5\n\t" \ "adc %2, %0, %1, lsl %6" \ : "=&r" (__lo), "=&r" (__hi), "=r" (__result) \ : "%r" (x), "r" (y), \ "M" (MAD_F_SCALEBITS), "M" (32 - MAD_F_SCALEBITS) \ : "cc"); \ __result; \ }) # endif # define MAD_F_MLX(hi, lo, x, y) \ asm ("smull %0, %1, %2, %3" \ : "=&r" (lo), "=&r" (hi) \ : "%r" (x), "r" (y)) # define MAD_F_MLA(hi, lo, x, y) \ asm ("smlal %0, %1, %2, %3" \ : "+r" (lo), "+r" (hi) \ : "%r" (x), "r" (y)) # define MAD_F_MLN(hi, lo) \ asm ("rsbs %0, %2, #0\n\t" \ "rsc %1, %3, #0" \ : "=r" (lo), "=r" (hi) \ : "0" (lo), "1" (hi) \ : "cc") # define mad_f_scale64(hi, lo) \ ({ mad_fixed_t __result; \ asm ("movs %0, %1, lsr %3\n\t" \ "adc %0, %0, %2, lsl %4" \ : "=&r" (__result) \ : "r" (lo), "r" (hi), \ "M" (MAD_F_SCALEBITS), "M" (32 - MAD_F_SCALEBITS) \ : "cc"); \ __result; \ }) # define MAD_F_SCALEBITS MAD_F_FRACBITS /* --- MIPS ---------------------------------------------------------------- */ # elif defined(FPM_MIPS) /* * This MIPS version is fast and accurate; the disposition of the least * significant bit depends on OPT_ACCURACY via mad_f_scale64(). */ # define MAD_F_MLX(hi, lo, x, y) \ asm ("mult %2,%3" \ : "=l" (lo), "=h" (hi) \ : "%r" (x), "r" (y)) # if defined(HAVE_MADD_ASM) # define MAD_F_MLA(hi, lo, x, y) \ asm ("madd %2,%3" \ : "+l" (lo), "+h" (hi) \ : "%r" (x), "r" (y)) # elif defined(HAVE_MADD16_ASM) /* * This loses significant accuracy due to the 16-bit integer limit in the * multiply/accumulate instruction. */ # define MAD_F_ML0(hi, lo, x, y) \ asm ("mult %2,%3" \ : "=l" (lo), "=h" (hi) \ : "%r" ((x) >> 12), "r" ((y) >> 16)) # define MAD_F_MLA(hi, lo, x, y) \ asm ("madd16 %2,%3" \ : "+l" (lo), "+h" (hi) \ : "%r" ((x) >> 12), "r" ((y) >> 16)) # define MAD_F_MLZ(hi, lo) ((mad_fixed_t) (lo)) # endif # if defined(OPT_SPEED) # define mad_f_scale64(hi, lo) \ ((mad_fixed_t) ((hi) << (32 - MAD_F_SCALEBITS))) # define MAD_F_SCALEBITS MAD_F_FRACBITS # endif /* --- SPARC --------------------------------------------------------------- */ # elif defined(FPM_SPARC) /* * This SPARC V8 version is fast and accurate; the disposition of the least * significant bit depends on OPT_ACCURACY via mad_f_scale64(). */ # define MAD_F_MLX(hi, lo, x, y) \ asm ("smul %2, %3, %0\n\t" \ "rd %%y, %1" \ : "=r" (lo), "=r" (hi) \ : "%r" (x), "rI" (y)) /* --- PowerPC ------------------------------------------------------------- */ # elif defined(FPM_PPC) /* * This PowerPC version is fast and accurate; the disposition of the least * significant bit depends on OPT_ACCURACY via mad_f_scale64(). */ # define MAD_F_MLX(hi, lo, x, y) \ do { \ asm ("mullw %0,%1,%2" \ : "=r" (lo) \ : "%r" (x), "r" (y)); \ asm ("mulhw %0,%1,%2" \ : "=r" (hi) \ : "%r" (x), "r" (y)); \ } \ while (0) # if defined(OPT_ACCURACY) /* * This gives best accuracy but is not very fast. */ # define MAD_F_MLA(hi, lo, x, y) \ ({ mad_fixed64hi_t __hi; \ mad_fixed64lo_t __lo; \ MAD_F_MLX(__hi, __lo, (x), (y)); \ asm ("addc %0,%2,%3\n\t" \ "adde %1,%4,%5" \ : "=r" (lo), "=r" (hi) \ : "%r" (lo), "r" (__lo), \ "%r" (hi), "r" (__hi) \ : "xer"); \ }) # endif # if defined(OPT_ACCURACY) /* * This is slower than the truncating version below it. */ # define mad_f_scale64(hi, lo) \ ({ mad_fixed_t __result, __round; \ asm ("rotrwi %0,%1,%2" \ : "=r" (__result) \ : "r" (lo), "i" (MAD_F_SCALEBITS)); \ asm ("extrwi %0,%1,1,0" \ : "=r" (__round) \ : "r" (__result)); \ asm ("insrwi %0,%1,%2,0" \ : "+r" (__result) \ : "r" (hi), "i" (MAD_F_SCALEBITS)); \ asm ("add %0,%1,%2" \ : "=r" (__result) \ : "%r" (__result), "r" (__round)); \ __result; \ }) # else # define mad_f_scale64(hi, lo) \ ({ mad_fixed_t __result; \ asm ("rotrwi %0,%1,%2" \ : "=r" (__result) \ : "r" (lo), "i" (MAD_F_SCALEBITS)); \ asm ("insrwi %0,%1,%2,0" \ : "+r" (__result) \ : "r" (hi), "i" (MAD_F_SCALEBITS)); \ __result; \ }) # endif # define MAD_F_SCALEBITS MAD_F_FRACBITS /* --- Default ------------------------------------------------------------- */ # elif defined(FPM_DEFAULT) /* * This version is the most portable but it loses significant accuracy. * Furthermore, accuracy is biased against the second argument, so care * should be taken when ordering operands. * * The scale factors are constant as this is not used with SSO. * * Pre-rounding is required to stay within the limits of compliance. */ # if defined(OPT_SPEED) # define mad_f_mul(x, y) (((x) >> 12) * ((y) >> 16)) # else # define mad_f_mul(x, y) ((((x) + (1L << 11)) >> 12) * \ (((y) + (1L << 15)) >> 16)) # endif /* ------------------------------------------------------------------------- */ # else # error "no FPM selected" # endif /* default implementations */ # if !defined(mad_f_mul) # define mad_f_mul(x, y) \ ({ register mad_fixed64hi_t __hi; \ register mad_fixed64lo_t __lo; \ MAD_F_MLX(__hi, __lo, (x), (y)); \ mad_f_scale64(__hi, __lo); \ }) # endif # if !defined(MAD_F_MLA) # define MAD_F_ML0(hi, lo, x, y) ((lo) = mad_f_mul((x), (y))) # define MAD_F_MLA(hi, lo, x, y) ((lo) += mad_f_mul((x), (y))) # define MAD_F_MLN(hi, lo) ((lo) = -(lo)) # define MAD_F_MLZ(hi, lo) ((void) (hi), (mad_fixed_t) (lo)) # endif # if !defined(MAD_F_ML0) # define MAD_F_ML0(hi, lo, x, y) MAD_F_MLX((hi), (lo), (x), (y)) # endif # if !defined(MAD_F_MLN) # define MAD_F_MLN(hi, lo) ((hi) = ((lo) = -(lo)) ? ~(hi) : -(hi)) # endif # if !defined(MAD_F_MLZ) # define MAD_F_MLZ(hi, lo) mad_f_scale64((hi), (lo)) # endif # if !defined(mad_f_scale64) # if defined(OPT_ACCURACY) # define mad_f_scale64(hi, lo) \ ((((mad_fixed_t) \ (((hi) << (32 - (MAD_F_SCALEBITS - 1))) | \ ((lo) >> (MAD_F_SCALEBITS - 1)))) + 1) >> 1) # else # define mad_f_scale64(hi, lo) \ ((mad_fixed_t) \ (((hi) << (32 - MAD_F_SCALEBITS)) | \ ((lo) >> MAD_F_SCALEBITS))) # endif # define MAD_F_SCALEBITS MAD_F_FRACBITS # endif /* C routines */ mad_fixed_t mad_f_abs(mad_fixed_t); mad_fixed_t mad_f_div(mad_fixed_t, mad_fixed_t); # endif