📄 basop32.c
字号:
/* v.2.0 - 15.Nov.2004
=============================================================================
U U GGG SSSS TTTTT
U U G S T
U U G GG SSSS T
U U G G S T
UUU GG SSS T
========================================
ITU-T - USER'S GROUP ON SOFTWARE TOOLS
========================================
=============================================================
COPYRIGHT NOTE: This source code, and all of its derivations,
is subject to the "ITU-T General Public License". Please have
it read in the distribution disk, or in the ITU-T
Recommendation G.191 on "SOFTWARE TOOLS FOR SPEECH AND AUDIO
CODING STANDARDS".
=============================================================
MODULE: BASOP32, BASIC OPERATORS
ORIGINAL BY:
Incorporated from anonymous contributions for
ETSI Standards as well as G.723.1, G.729, and G.722.1
DESCRIPTION:
This file contains the definition of 16- and 32-bit basic
operators to be used in the implementation of signal
processing algorithms. The basic operators try to resemble
assembly language instructions that are commonly found in
digital signal processor (DSP) CPUs, thus allowing algorithm
C-code implementations more directly mapeable to DSP assembly
code.
*********************************************************
NOTE: so far, this module does not have a demo program!
*********************************************************
FUNCTIONS:
Defined in basop32.h. Self-documentation within each function.
HISTORY:
26.Jan.00 v1.0 Incorporated to the STL from updated G.723.1/G.729
basic operator library (based on basicop2.c) and
G.723.1's basop.c [L_mls(), div_l(), i_mult()]
05.Jul.00 v1.1 Added 32-bit shiftless accumulation basic
operators (L_msu0, L_mac0, L_mult0). Improved
documentation for i_mult().
03 Nov 04 v2.0 Incorporation of new 32-bit / 40-bit / control
operators for the ITU-T Standard Tool Library as
described in Geneva, 20-30 January 2004 WP 3/16 Q10/16
TD 11 document and subsequent discussions on the
wp3audio@yahoogroups.com email reflector.
norm_s() weight reduced from 15 to 1.
norm_l() weight reduced from 30 to 1.
L_abs() weight reduced from 2 to 1.
L_add() weight reduced from 2 to 1.
L_negate() weight reduced from 2 to 1.
L_shl() weight reduced from 2 to 1.
L_shr() weight reduced from 2 to 1.
L_sub() weight reduced from 2 to 1.
mac_r() weight reduced from 2 to 1.
msu_r() weight reduced from 2 to 1.
mult_r() weight reduced from 2 to 1.
L_deposit_h() weight reduced from 2 to 1.
L_deposit_l() weight reduced from 2 to 1.
15 Nov 04 v2.0 L_mls() weight of 5.
div_l() weight of 32.
i_mult() weight of 3.
=============================================================================
*/
/*___________________________________________________________________________
| |
| Basic arithmetic operators. |
| |
| $Id $ |
| |
| saturate() |
| add() |
| sub() |
| abs_s() |
| divide_s() |
| extract_h() |
| extract_l() |
| L_abs() |
| L_add() |
| L_deposit_h() |
| L_deposit_l() |
| L_mac() |
| L_msu() |
| L_mult() |
| L_negate() |
| L_shl() |
| L_shr() |
| L_sub() |
| mac_r() |
| msu_r() |
| mult() |
| mult_r() |
| negate() |
| norm_l() |
| norm_s() |
| round() |
| shl() |
| shr() |
|___________________________________________________________________________|
*/
/*___________________________________________________________________________
| |
| Include-Files |
|___________________________________________________________________________|
*/
#include <stdio.h>
#include <stdlib.h>
#include "stl.h"
#if (WMOPS)
extern BASIC_OP multiCounter[MAXCOUNTERS];
extern int currCounter;
#endif
/*___________________________________________________________________________
| |
| Local Functions |
|___________________________________________________________________________|
*/
Word16 saturate (Word32 L_var1);
/*___________________________________________________________________________
| |
| Constants and Globals |
|___________________________________________________________________________|
*/
Flag Overflow = 0;
Flag Carry = 0;
/*___________________________________________________________________________
| |
| Functions |
|___________________________________________________________________________|
*/
/*___________________________________________________________________________
| |
| Function Name : saturate |
| |
| Purpose : |
| |
| Limit the 32 bit input to the range of a 16 bit word. |
| |
| Inputs : |
| |
| L_var1 |
| 32 bit long signed integer (Word32) whose value falls in the |
| range : 0x8000 0000 <= L_var1 <= 0x7fff ffff. |
| |
| Outputs : |
| |
| none |
| |
| Return Value : |
| |
| var_out |
| 16 bit short signed integer (Word16) whose value falls in the |
| range : 0xffff 8000 <= var_out <= 0x0000 7fff. |
|___________________________________________________________________________|
*/
Word16 saturate (Word32 L_var1)
{
Word16 var_out;
if (L_var1 > 0X00007fffL)
{
Overflow = 1;
var_out = MAX_16;
}
else if (L_var1 < (Word32) 0xffff8000L)
{
Overflow = 1;
var_out = MIN_16;
}
else
{
var_out = extract_l (L_var1);
#if (WMOPS)
multiCounter[currCounter].extract_l--;
#endif
}
return (var_out);
}
/*___________________________________________________________________________
| |
| Function Name : add |
| |
| Purpose : |
| |
| Performs the addition (var1+var2) with overflow control and saturation;|
| the 16 bit result is set at +32767 when overflow occurs or at -32768 |
| when underflow occurs. |
| |
| Complexity weight : 1 |
| |
| Inputs : |
| |
| var1 |
| 16 bit short signed integer (Word16) whose value falls in the |
| range : 0xffff 8000 <= var1 <= 0x0000 7fff. |
| |
| var2 |
| 16 bit short signed integer (Word16) whose value falls in the |
| range : 0xffff 8000 <= var1 <= 0x0000 7fff. |
| |
| Outputs : |
| |
| none |
| |
| Return Value : |
| |
| var_out |
| 16 bit short signed integer (Word16) whose value falls in the |
| range : 0xffff 8000 <= var_out <= 0x0000 7fff. |
|___________________________________________________________________________|
*/
Word16 add (Word16 var1, Word16 var2)
{
Word16 var_out;
Word32 L_sum;
L_sum = (Word32) var1 + var2;
var_out = saturate (L_sum);
#if (WMOPS)
⌨️ 快捷键说明
复制代码
Ctrl + C
搜索代码
Ctrl + F
全屏模式
F11
切换主题
Ctrl + Shift + D
显示快捷键
?
增大字号
Ctrl + =
减小字号
Ctrl + -