HP UX Developer Tools manual Registers by using an L or R suffix

	Program Structure
	Registers and Register Mnemonics
	In addition, on PA-RISC 1.1, 2.0. and 2.0W the left and right halves of
	the floating-point registers can be accessed as separate single-precision
	registers by using an L or R suffix.
	For example, %fr8R accesses the right-most 32 bits of %fr8 as a
	single-precision number.
	The L or R suffixes can only be used on the predefined floating-point
	registers in the form %frnn, where nn is the register number. It is not
	legal to use L or R with an integer value. For example, %fr8R is legal; 8R
	is not legal.
	The space registers form the basis of the virtual memory system. Each of
	the eight space registers can hold a 16- or 32-bit space identifier,
	depending on the hardware model. The space registers are denoted as
	%sr0 through %sr7. Space register %sr0 is set implicitly by the BLE
	instruction, and space registers %sr5 through %sr7 cannot be modified
	except by code running at the most privileged level.
	The control registers contain system-state information. There are 25
	control registers, denoted as %cr0 and %cr8 through %cr31. Of these
	registers, only %cr11 (%sar), the shift amount register, and %cr16
	(%itmt), the interval timer, are normally accessible to the user-level
	programmer. The other registers are accessed only by code running at
	the most privileged level.
	Register operands are denoted by register-typed constants because the
	Assembler needs to be able to differentiate between general registers,
	space registers, floating point registers, and ordinary integer constants.
	To make assembly code more readable, you can use the .REG directive to
	declare a symbolic name as an alias for a predefined register. The
	predefined registers have a register type associated with them. The
	Assembler enforces register type checking and issues a warning message
	if the wrong kind of register is used within an operand. A warning is also
	issued when an integer constant or absolute expression is found where a
	register is expected. You must use the .REG directive to define symbolic
	register names. If a symbolic name defined in an .EQU directive is used
	where a register symbol is expected, the Assembler issues a warning
	message, because it considers an .EQU defined symbol to be a simple
	integer constant.
	If an absolute expression is used instead of a register or register-typed
NOTE
	symbol name, the Assembler issues warning message number 41.

24 Chapter 2