Propeller Manual

FIT – Assembly Language Reference
Page 292 · Propeller Manual v1.1
FIT
Directive: Validate that previous instructions/data fit entirely below a specific address.
FIT 〈Address〉
Result: Compile-time error if previous instructions/data exceed Address-1.
• Address is an optional Cog RAM address (0-$1F0) for which prior assembly code
should not reach. If Address is not given, the value $1F0 is used (the address of the
first special purpose register).
Explanation
The
FIT directive checks the current compile-time cog address pointer and generates an error
if it is beyond Address-1 or if it is beyond $1EF (the end of general purpose Cog RAM). This
directive can be used to ensure that the previous instructions and data fit within Cog RAM, or
a limited region of Cog RAM. Note: any instructions that do not fit in Cog RAM will be left
out when the assembly code is launched into the cog. Consider the following example:
DAT
ORG 492
Toggle mov dira, Pin
:Loop mov outa, Pin
mov outa, #0
jmp #:Loop
Pin long $1000
FIT
This code was artificially pushed into upper Cog RAM space by the ORG statement, causing
the code to overlap the first special purpose register ($1F0) and causing the
FIT directive to
cause a compile-time error when the code is compiled.
T