util.txt

来自「汇编编程艺术」· 文本 代码 · 共 309 行

Utility Routines
----------------

The following routines are all Utility Routines.  The first routines listed
below compute the number of print positions required by a 16-bit and 32-bit
signed and unsigned integer value.  UlSize is like the LSize except it treats
the value in DX:AX as an unsigned long integer.  The next set of routines in
this section check the character in the AL register to see whether it is a
hexidecimal digit, if it alphabetic, if it is a lower case alphabetic, if it
is a upper case alphabetic, and if it is numeric.  Then there are some
miscellaneous routines (macros) which process command line parameters, invoke
DOS and exit the program.



Routine:  ISize
---------------

Category:            Utility Routine

Register on entry:   AX- 16-bit value to compute the
				output size for.

Register on return:  AX- Number of print positions
				required by this number (including
				the minus sign, if necessary).

Flags affected:      None

Example of usage:
		     mov     ax, I
		     ISize
		     puti                    ;Prints positions
					     ;req'd by I.


Description:         This routine computes the number of print positions
		     required by a 16-bit signed integer value.  ISize computes
		     the minimum number of character positions it takes to print
		     the signed decimal value in the AX register.  If the number
		     is negative, it will include space for the minus sign in
		     the count.


Include:             stdlib.a or util.a




Routine:  USize
---------------

Category:            Utility Routine

Register on entry:   AX- 16 bit value to compute the
				output size for

Register on return:  AX- number of print positions
			 required by this number (including
			 the minus sign, if necessary)

Flags affected:      None

Example of usage:
		     mov     ax, I
		     USize
		     puti                    ;prints position
					     ;required by I


Description:         This routine computes the number of print positions
		     required by a 16-bit signed integer value.  It also
		     computes the number of print positions required by a
		     16-bit unsigned value.  USize computes the minimum number
		     of character positions it will take to print an unsigned
		     decimal value in the AX register.  If the number is
		     negative, it will include space for the minus sign in the
		     count.


Include:             stdlib.a or util.a


Routine:  LSize
---------------

Category:            Utility Routine

Register on entry:   DX:AX   - 32-bit value to compute the
			       output size for.

Register on return:  AX - Number of print positions
			  required by this number (including
			  the minus sign, if necessary).

Flags affected:      None

Example of Usage:
		     mov     ax, word ptr L
		     mov     dx, word ptr L+2
		     LSize
		     puti                    ;Prints positions
					     ;req'd by L.


Description:         This routine computes the number of print positions
		     required by a 32-bit signed integer value.  LSize computes
		     the minimum number of character positions it will take to
		     print the signed decimal value in the DX:AX registers.  If
		     the number is negative, it will include space for the minus
		     sign in the count.


Include:             stdlib.a or util.a



Routine:  ULSize
----------------

Category:             Utility Routine

Registers on Entry:   DX:AX - 32-bit value to compute the output size for.

Registers on return:  AX - number of print positions required by this number

Flags affected:       None

Example of Usage:
		      mov     ax, word ptr L
		      mov     dx, word ptr L+2
		      ULSize
		      puti                    ; Prints positions req'd by L


Description:          ULSize computes the minimum number of character
		      positions it will take to print an unsigned decimal
		      value in the DX:AX registers.


Include:              stdlib.a or util.a



Routine:  IsAlNum
-----------------

Category:             Utility routine

Register on entry:    AL - character to check.

Register on return:   None

Flags affected:       Zero flag - set if character is alphanumeric,
		      clear if not.


Example of usage :    mov al, char
		      IsAlNum
		      je IsAlNumChar


Description :         This routine checks the character in the AL register to
		      see if it is in the range A-Z, a-z, or 0-9.  Upon return,
		      you can use the JE instruction to check to see if the
		      character was in this range (or, conversely, you can use
		      JNE to see if it is not in range).


Include:              stdlib.a or util.a


Routine:  IsXDigit
------------------

Category:               Utility Routine

Register on Entry:     AL- character to check

Registers on Return:    None

Flags Affected:         Zero flag-  Set if character is a hex digit, clear if not


Example of Usage:       mov    al, char
			IsXDigit
			je     IsXDigitChar


Description:            This routine checks the character in the AL register to
			see if it is in the range A-F, a-f, or 0-9.  Upon
			return, you can use the JE instruction to check to see
			if the character was in this range (or, conversely,
			you can use jne to see if it is not in the range).


Include:                stdlib.a or util.a


Routine:   IsDigit
------------------

Category:            Utility Routine

Register on entry:   AL- Character to check

Register on return:  None

Flags affected:	     Zero flag- set if character is numeric, clear if not.

Example of Usage:    mov   al, char
		     IsDigit
		     je  IsDecChar


Description:         This routine checks the character in the AL register to
		     see if it is in the range 0-9.  Upon return, you can use
		     the JE instruction to check to see if the character was
		     in the range (or, conversely, you can use JNE to see if it
		     is not in the range).


Include:             stdlib.a or util.a


Routine:   IsAlpha
------------------

Category:            Utility Routine

Register on entry:   AL- Character to check

Register on return:  None

Flags affected:	     Zero flag- set if character is alphabetic, clear if not.

Example of Usage:    mov   al, char
		     IsAlpha
		     je   IsAlChar


Description:         This routine checks the character in the AL register to
		     see if it is in the range A-Z or a-z.  Upon return, you
		     can use the JE instruction to check to see if the character
		     was in the range (or, conversely, you can use JNE to see
		     if it is not in the range).

Include:             stdlib.a or util.a




Routine: IsLower
----------------

Category:             Utility Routine

Registers on Entry:   AL- character to test

Registers on Return:  None


Flags Affected:       Zero = 1 if character is a lower case alphabetic character
		      Zero = 0 if character is not a lower case alphabetic
		      character

Example of Usage:     mov  AL, char        ; put char in AL
		      IsLower              ; is char lower a-z?
		      je  IsLowerChar      ; if yes, jump to IsLowerChar


Description:          This routine checks the character in the AL register to
		      see if it is in the range a-z.  Upon return, you can use
		      the JE instruction to check and see if the character was
		      in this range (or you can use JNE to check and see if
		      the character was not in this range).  This procedure is
		      implemented as a macro for high performance.


Include:              stdlib.a or util.a


Routine:  IsUpper
-----------------

Category:             Utility Routine

Registers on Entry:   AL- character to check

Registers on Return:  None

Flags Affected:       Zero flag - set if character is uppercase alpha, clear
				  if not.


Example of Usage:     mov al, char
		      IsUpper
		      je IsUpperChar


Description:          This routine checks the character in the AL register to
		      see if it is in the ranger A-Z.  Upon return, you can use
		      the JE instruction to check to see if it not in the
		      range).  It uses macro implementation for high performance.


Include:              stdlib.a or util.a