home .. forth .. misc mail list archive ..

No Subject


On Tue, 18 Apr 1995 rockwell@nova.umd.edu wrote:

> Consider this instruction sequence:
> a!  @+  a   dup
> dup -or com nop
> +
> 
> This is a distillation of the steps used to increment then decrement
> the stack pointer.  Let's say that TOS is set to pattern 000001, and


Could someone explain to me how instructions are sequenced?  Why is
the nop *before* the +?  I would expect the sequence to go:
+ nop nop nop <instruction fetch>
or:
--- --- --- + <instruction fetch>

So that nops are required *after* the +, or an instruction fetch to allow
for carry prop.  Thanks.

-Dave