ITU-T g729原版源代码

/* Version 3.3 Last modified: December 26, 1995 */ /*___________________________________________________________________________ | | | Basics operators. | |___________________________________________________________________________| */ /*___________________________________________________________________________ | | | Include-Files | |___________________________________________________________________________| */ #include <stdio.h> #include <stdlib.h> #include "typedef.h" #include "basic_op.h" /*___________________________________________________________________________ | | | Local Functions | |___________________________________________________________________________| */ Word16 sature(Word32 L_var1); /*___________________________________________________________________________ | | | Constants and Globals | |___________________________________________________________________________| */ Flag Overflow =0; Flag Carry =0; /*___________________________________________________________________________ | | | Functions | |___________________________________________________________________________| */ /*___________________________________________________________________________ | | | Function Name : sature | | | | 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 sature(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 { Overflow = 0; var_out = extract_l(L_var1); } 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_somme; L_somme = (Word32) var1 + var2; var_out = sature(L_somme); return(var_out); } /*___________________________________________________________________________ | | | Function Name : sub | | | | Purpose : | | | | Performs the subtraction (var1+var2) with overflow control and satu- | | ration; the 16 bit result is set at +32767 when overflow occurs or at | | -32768 when underflow occurs. | | | | Complexity weight : 1 | | | | Inputs : | | | |