Diff: fixed.h

Revision:

0:7627c79db971

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/fixed.h	Fri Nov 26 12:18:30 2010 +0000
@@ -0,0 +1,501 @@
+/*
+ * 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 1.1 2010/11/23 20:12:57 andy Exp $
+ */
+
+# ifndef LIBMAD_FIXED_H
+# define LIBMAD_FIXED_H
+
+#include "config.h"
+
+# if SIZEOF_INT >= 4
+typedef   signed int mad_fixed_t;
+
+typedef   signed int mad_fixed64hi_t;
+typedef unsigned int mad_fixed64lo_t;
+# else
+typedef   signed long mad_fixed_t;
+
+typedef   signed long mad_fixed64hi_t;
+typedef unsigned long mad_fixed64lo_t;
+# endif
+
+# if defined(_MSC_VER)
+#  define mad_fixed64_t  signed __int64
+# elif 1 || defined(__GNUC__)
+#  define mad_fixed64_t  signed long long
+# endif
+
+# 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
+
+# if MAD_F_FRACBITS == 28
+#  define MAD_F(x)		((mad_fixed_t) (x##L))
+# else
+#  if MAD_F_FRACBITS < 28
+#   warning "MAD_F_FRACBITS < 28"
+#   define MAD_F(x)		((mad_fixed_t)  \
+				 (((x##L) +  \
+				   (1L << (28 - MAD_F_FRACBITS - 1))) >>  \
+				  (28 - MAD_F_FRACBITS)))
+#  elif MAD_F_FRACBITS > 28
+#   error "MAD_F_FRACBITS > 28 not currently supported"
+#   define MAD_F(x)		((mad_fixed_t)  \
+				 ((x##L) << (MAD_F_FRACBITS - 28)))
+#  endif
+# endif
+
+# 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