Echelon Neuron - Manual (Page 80)

BR (Branch)
The BR instruction performs an unconditional branch. The BR instruction uses
the relative addressing mode. The BR instruction branches forward or backward
with a signed relative displacement of -126 to +129 bytes. The displacement
expression must resolve at link time to a value in the range -128 to +127 (two less
than the actual displacement because the displacement calculation includes the
size of the BR operation itself).
The Neuron Assembler also supports the use of a label for the displacement
expression; manual calculation of the displacement value is not required.
See also BRF (Branch Far) for a longer unconditional branch and SBR (Short
Branch) for a shorter unconditional forward branch.
The BR instruction applies to Series 3100, 5000, and 6000 devices.
Syntax:
The BR instruction requires a single operand to specify the displacement or
label:
BR displacement
BR label
Table 16 describes the attributes of the BR instruction.
Table 16. BR Instruction
Instruction Hexadecimal
Opcode
Instruction
Size (Bytes)
CPU Cycles
Required
Affect on
Carry Flag
BR 71 2 2 None
Example:
The following example shows two functions that share a common set of code. The
BR instruction branches unconditionally from the end of one function to the
Common label to run the common code.
Sub_B ... ; subroutine B
br Common
Sub_A ... ; subroutine A
Common ... ; common code
ret ; return to caller
70 Neuron Assembly Language Instruction Statements