Control Statements

The A166 Assembler provides a number of control statements that permit you to define symbol values, reserve and initialize storage, and control the placement of your code.

These statements should not be confused with processor instructions or with assembler directives. They do not produce executable code and, with the exception of the DB, DD, DW, DBPTR, DSPTR, and DPPTR statements, they have no direct effect on the contents of code memory. These controls change the state of the assembler, define user symbols, and add information to the object file.

Control statements may be divided into the following categories:

Address Control

Statement	Description
EVEN	Forces the location counter to the next even address.
ORG	Sets the location counter to a specific offset or address.

Conditional Assembly

Statement	Description
IF	Begins an IF-ELSE-ENDIF block.
ELSEIF	Begins an alternate IF block.
ELSE	Begins an ELSE block.
ENDIF	Terminates an IF block.

Group Definition

Statement	Description
CGROUP	Defines a group of code sections.
DGROUP	Defines a group of data sections.

Memory Initialization

Statement	Description
DB	Allocates memory for one or more defined byte values.
DD	Allocates memory for one or more defined double word values.
DW	Allocates memory for one or more defined word values.
DBPTR	Allocates memory for a bit pointer.
DPPTR	Allocates memory for a page pointer.
DSPTR	Allocates memory for a segment pointer.

Memory Reservation

Statement	Description
DBIT	Reserves space for one or more bits.
DEFA	Defines on-chip RAM symbols.
DEFB	Defines bit symbols.
DEFR	Defines SFR symbols.
DS	Reserves space for one or more bytes.
DSB	Reserves space for one or more bytes.
DSD	Reserves space for one or more double words.
DSW	Reserves space for one or more words.
PECDEF	Reserves space for a PEC channel.
REGBANK	Reserves space for a register bank.
REGDEF	Reserves space for a register bank.
SSKDEF	Reserves space for the system stack.

Procedure Declaration

Statement	Description
ENDP	Defines the end of a function.
LABEL	Assigns an address to a symbolic name.
PROC	Defines the beginning of a function.

Program Linkage

Statement	Description
EXTERN	Defines external symbols.
EXTRN	Defines external symbols.
GLOBAL	Defines global symbols.
NAME	Specifies the name of the current module.
PUBLIC	Defines symbols which may be used in other modules.

Section Definition

Statement	Description
ENDS	Marks the end of a section.
SECTION	Defines a logical memory section.

Symbol Definition

Statement	Description
BIT	Defines an address in bit space.
EQU	Sets a permanent symbol value.
LIT	Assigns a text string to a symbol name.
SET	Sets or resets a symbol value.

Miscellaneous

Statement	Description
ASSUME	Specifies contents of DPP registers.
END	Signals the end of the assembly module.
TYPEDEC	Specifies the type for forward references symbols.

Control Statements