Library /sys$common/syshlp/sda.hlb Expressions  *Conan The Librarian (sorry for the slow response - running on an old VAX)

     Some SDA commands allow expressions as command parameters.
     To create expressions, you can use

     	  Radix operators
 	  Arithmetic and logical operators
 	  Precedence operators
 	  Symbols
 	  Numerals

     Radix operators specify a given radix for the number that follows
     the operator.  SDA displays hexadecimal numbers with leading zeros
     and displays decimal numbers with leading spaces.

 	^X	Hexadecimal (default)
 	^O	Octal
 	^D	Decimal

     Unary operators

 	#	Logical NOT of value
 	+	Assigns positive value (default)
 	-	Assigns negative value
 	@	Uses contents of location
 	G	Adds ^X80000000 to value (system space)
 	H	Adds ^X7FFE0000 to value (control region)

     Binary operators

 	+	Addition
 	-	Subtraction
 	&	Logical AND
 	!	Logical OR
 	\	Logical XOR
 	*	Multiplication
 	/	Division
 	@	Arithmetic shift

 	Logical AND, logical OR, logical XOR, multiplication, division, and
 	arithmetic shifting are performed before addition and subtraction.

     Precedence operators

 	Parentheses control the evaluation of all operations.  Expressions
 	enclosed in parentheses are evaluated first.  SDA evaluates nested
 	parenthetical expressions from the innermost to the outermost pairs
 	of parentheses.

     Symbols

 	Symbols are composed of up to 31 letters and numbers, and
 	can include the dollar sign and underscore characters.  When you
 	invoke SDA, it copies the global symbols from SYS.STB, the system's
 	symbol table.  You can add other symbols to SDA's symbol table by
         using the DEFINE and READ commands.  SDA also predefines certain
         symbols, some of which follow:

 	.	Current location
 	G	^X80000000 (system space)
 	H	^X7FFE0000 (control region)
 	R0-R11	General registers
 	AP	Argument pointer
 	FP	Frame pointer
 	SP	Stack pointer
 	PC	Program counter
 	PSL	Processor status longword

 	For a complete list of SDA predefined symbols, type HELP SYMBOLS