Category : Assembly Language Source Code
Archive   : C--C0200.ZIP
Filename : MATH.H--

/*
SPHINX Programming (C) 1993.
NAME: MATH.H--
DESCRIPTION: This file contains some math procedure definitions.
PROCEDURES DEFINED IN THIS FILE ARE:
: int ABS(number)
: word SQRT(number)
: dword SQRT_386(number) // NOT YET TESTED!!! 🙂
*/


: int ABS () /* AX = signed number to get absolute value of */
{
IF( int AX < 0 )
-AX;
}
/* Returns: AX = absolute value
*/


: word SQRT () /* AX = number to root */
{$ MOV BX,128 // initial guess
$ MOV DI,BX
$ MOV CX,AX
TOP:
$ MOV AX,CX
$ XOR DX,DX
$ DIV BX
$ ADD AX,BX
$ SHR AX,1
$ CMP AX,BX
$ JE FINISHED
$ CMP AX,DI
$ MOV DI,BX
$ MOV BX,AX
$ JNE TOP
$ CMP AX,DI
$ JL FINISHED
$ MOV AX,DI
FINISHED:
}
/* returns: AX = square root
BX,CX,DX,DI = undefined
*/


: dword SQRT_386 () /* EAX = number to root */
{$ MOV EBX,32768 // initial guess
$ MOV EDI,EBX
$ MOV ECX,EAX
TOP:
$ MOV EAX,ECX
$ XOR EDX,EDX
$ DIV EBX
$ ADD EAX,EBX
$ SHR EAX,1
$ CMP EAX,EBX
$ JE FINISHED
$ CMP EAX,EDI
$ MOV EDI,EBX
$ MOV EBX,EAX
$ JNE TOP
$ CMP EAX,EDI
$ JL FINISHED
$ MOV EAX,EDI
FINISHED:
}
/* returns: EAX = square root
EBX,ECX,EDX,EDI = undefined
*/


/* end of MATH.H-- */