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(as.info)PDP-11-Syntax

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PDP-11 Assembly Language Syntax
-------------------------------

   `as' supports both DEC syntax and BSD syntax.  The only difference
is that in DEC syntax, a `#' character is used to denote an immediate
constants, while in BSD syntax the character for this purpose is `$'.

   eneral-purpose registers are named `r0' through `r7'.  Mnemonic
alternatives for `r6' and `r7' are `sp' and `pc', respectively.

   Floating-point registers are named `ac0' through `ac3', or
alternatively `fr0' through `fr3'.

   Comments are started with a `#' or a `/' character, and extend to
the end of the line.  (FIXME: clash with immediates?)