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Diffstat (limited to 'media/libstagefright/codecs/amrwbenc/src/oper_32b.c')
| -rw-r--r-- | media/libstagefright/codecs/amrwbenc/src/oper_32b.c | 223 |
1 files changed, 223 insertions, 0 deletions
diff --git a/media/libstagefright/codecs/amrwbenc/src/oper_32b.c b/media/libstagefright/codecs/amrwbenc/src/oper_32b.c new file mode 100644 index 0000000..27cad76 --- /dev/null +++ b/media/libstagefright/codecs/amrwbenc/src/oper_32b.c @@ -0,0 +1,223 @@ +/* + ** Copyright 2003-2010, VisualOn, Inc. + ** + ** Licensed under the Apache License, Version 2.0 (the "License"); + ** you may not use this file except in compliance with the License. + ** You may obtain a copy of the License at + ** + ** http://www.apache.org/licenses/LICENSE-2.0 + ** + ** Unless required by applicable law or agreed to in writing, software + ** distributed under the License is distributed on an "AS IS" BASIS, + ** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + ** See the License for the specific language governing permissions and + ** limitations under the License. + */ + +/***************************************************************************** + * This file contains operations in double precision. * + * These operations are not standard double precision operations. * + * They are used where single precision is not enough but the full 32 bits * + * precision is not necessary. For example, the function Div_32() has a * + * 24 bits precision which is enough for our purposes. * + * * + * The double precision numbers use a special representation: * + * * + * L_32 = hi<<16 + lo<<1 * + * * + * L_32 is a 32 bit integer. * + * hi and lo are 16 bit signed integers. * + * As the low part also contains the sign, this allows fast multiplication. * + * * + * 0x8000 0000 <= L_32 <= 0x7fff fffe. * + * * + * We will use DPF (Double Precision Format )in this file to specify * + * this special format. * + ***************************************************************************** +*/ +#include "typedef.h" +#include "basic_op.h" +#include "oper_32b.h" + +/***************************************************************************** + * * + * Function L_Extract() * + * * + * Extract from a 32 bit integer two 16 bit DPF. * + * * + * Arguments: * + * * + * L_32 : 32 bit integer. * + * 0x8000 0000 <= L_32 <= 0x7fff ffff. * + * hi : b16 to b31 of L_32 * + * lo : (L_32 - hi<<16)>>1 * + ***************************************************************************** +*/ + +__inline void VO_L_Extract (Word32 L_32, Word16 *hi, Word16 *lo) +{ + *hi = (Word16)(L_32 >> 16); + *lo = (Word16)((L_32 & 0xffff) >> 1); + return; +} + +/***************************************************************************** + * * + * Function L_Comp() * + * * + * Compose from two 16 bit DPF a 32 bit integer. * + * * + * L_32 = hi<<16 + lo<<1 * + * * + * Arguments: * + * * + * hi msb * + * lo lsf (with sign) * + * * + * Return Value : * + * * + * 32 bit long signed integer (Word32) whose value falls in the * + * range : 0x8000 0000 <= L_32 <= 0x7fff fff0. * + * * + ***************************************************************************** +*/ + +Word32 L_Comp (Word16 hi, Word16 lo) +{ + Word32 L_32; + + L_32 = L_deposit_h (hi); + + return (L_mac (L_32, lo, 1)); /* = hi<<16 + lo<<1 */ +} + +/***************************************************************************** + * Function Mpy_32() * + * * + * Multiply two 32 bit integers (DPF). The result is divided by 2**31 * + * * + * L_32 = (hi1*hi2)<<1 + ( (hi1*lo2)>>15 + (lo1*hi2)>>15 )<<1 * + * * + * This operation can also be viewed as the multiplication of two Q31 * + * number and the result is also in Q31. * + * * + * Arguments: * + * * + * hi1 hi part of first number * + * lo1 lo part of first number * + * hi2 hi part of second number * + * lo2 lo part of second number * + * * + ***************************************************************************** +*/ + +__inline Word32 Mpy_32 (Word16 hi1, Word16 lo1, Word16 hi2, Word16 lo2) +{ + Word32 L_32; + L_32 = (hi1 * hi2); + L_32 += (hi1 * lo2) >> 15; + L_32 += (lo1 * hi2) >> 15; + L_32 <<= 1; + + return (L_32); +} + +/***************************************************************************** + * Function Mpy_32_16() * + * * + * Multiply a 16 bit integer by a 32 bit (DPF). The result is divided * + * by 2**15 * + * * + * * + * L_32 = (hi1*lo2)<<1 + ((lo1*lo2)>>15)<<1 * + * * + * Arguments: * + * * + * hi hi part of 32 bit number. * + * lo lo part of 32 bit number. * + * n 16 bit number. * + * * + ***************************************************************************** +*/ + +__inline Word32 Mpy_32_16 (Word16 hi, Word16 lo, Word16 n) +{ + Word32 L_32; + + L_32 = (hi * n)<<1; + L_32 += (((lo * n)>>15)<<1); + + return (L_32); +} + +/***************************************************************************** + * * + * Function Name : Div_32 * + * * + * Purpose : * + * Fractional integer division of two 32 bit numbers. * + * L_num / L_denom. * + * L_num and L_denom must be positive and L_num < L_denom. * + * L_denom = denom_hi<<16 + denom_lo<<1 * + * denom_hi is a normalize number. * + * * + * Inputs : * + * * + * L_num * + * 32 bit long signed integer (Word32) whose value falls in the * + * range : 0x0000 0000 < L_num < L_denom * + * * + * L_denom = denom_hi<<16 + denom_lo<<1 (DPF) * + * * + * denom_hi * + * 16 bit positive normalized integer whose value falls in the * + * range : 0x4000 < hi < 0x7fff * + * denom_lo * + * 16 bit positive integer whose value falls in the * + * range : 0 < lo < 0x7fff * + * * + * Return Value : * + * * + * L_div * + * 32 bit long signed integer (Word32) whose value falls in the * + * range : 0x0000 0000 <= L_div <= 0x7fff ffff. * + * * + * Algorithm: * + * * + * - find = 1/L_denom. * + * First approximation: approx = 1 / denom_hi * + * 1/L_denom = approx * (2.0 - L_denom * approx ) * + * * + * - result = L_num * (1/L_denom) * + ***************************************************************************** +*/ + +Word32 Div_32 (Word32 L_num, Word16 denom_hi, Word16 denom_lo) +{ + Word16 approx, hi, lo, n_hi, n_lo; + Word32 L_32; + + /* First approximation: 1 / L_denom = 1/denom_hi */ + + approx = div_s ((Word16) 0x3fff, denom_hi); + + /* 1/L_denom = approx * (2.0 - L_denom * approx) */ + + L_32 = Mpy_32_16 (denom_hi, denom_lo, approx); + + L_32 = L_sub ((Word32) 0x7fffffffL, L_32); + hi = L_32 >> 16; + lo = (L_32 & 0xffff) >> 1; + + L_32 = Mpy_32_16 (hi, lo, approx); + + /* L_num * (1/L_denom) */ + hi = L_32 >> 16; + lo = (L_32 & 0xffff) >> 1; + VO_L_Extract (L_num, &n_hi, &n_lo); + L_32 = Mpy_32 (n_hi, n_lo, hi, lo); + L_32 = L_shl2(L_32, 2); + + return (L_32); +} + |