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--------------------------------------------------------------------------
Apoo Assembly Language
---------------------------------------------------------------------------
Apoo has a set of general purpose registers (32 by default), a data
memory area, a program memory area, a system stack and a program
counter register.
All memory cells and registers have 32 bits.
Registers: R0,R1,R2,R3,R4,R5,R6,R7, ...
Memory Data:
-----------
Memory cells are created as needed. We can reserve memory cells
in two ways, using the following pseudo-instructions:
Pseudo-instructions:
-------------------
Meaning
-------------------------------------------------
<Label:> mem n reserves n memory addresses
-------------------------------------------------
Label: const n2 contents of memory address
const n1 Label is n1, of Label+1 is n2
Label is any string beginning with a letter and containing only letters
and digits with the exception of legal register names. If exists, must
begin in the first column of a line
NOTE: Every memory address refered, must have been reserved by
one of the previous pseudo-instructions.
E.g. the instruction "load 3 R2", will cause an "Out of Memory" error, if
at least "mem 3" or three "const" pseudo-instructions were not given...
System Stack
------------
A special memory area used to implement subroutines. We can only push
a value to the Stack and pop a value from it (the one in the
top of the Stack).
It is used by the instructions jsr and rtn.
It can be manipulated by means of the {\tt push} and {\tt pop} instructions.
Instruction form
----------------
<Label:> Operation <Operand1> <Operand2>
Label is any string of letters or digits; if exists, must begin in the
first column of a line
Comments
--------
A line beginnig with # will be ignored by the parser; so it can be
used to write comments of the program
Instruction Set
---------------
--------------------------------------------------------------------------
Operation Operand1 Operand2 Meanning
--------------------------------------------------------------------------
load Mem Ri loads contents of memory
address Mem into register Ri;
Mem can be a label
--------------------------------------------------------------------------
loadn Num Ri loads number Num into register
Ri; Num can be a label
--------------------------------------------------------------------------
loadi Ri Rj loads contents of memory
which address is the contents
of Ri into Rj (indirect load)
--------------------------------------------------------------------------
store Ri Mem stores contents of Ri at memory
address Mem; Mem can be a label
--------------------------------------------------------------------------
storer Ri Rj stores contents of Ri into Rj
--------------------------------------------------------------------------
storei Ri Rj stores contents of Ri
into at memory address, which is the
contents of Rj
--------------------------------------------------------------------------
add Ri Rj add contents of register Ri to
contents of register Rj, and
stores into Rj (Rj=Ri+Rj)
--------------------------------------------------------------------------
sub Ri Rj subtracts contents of register
Rj from contents of register Rj
and stores into Rj (Rj=Ri-Rj)
--------------------------------------------------------------------------
mul Ri Rj multiplies contents of register
Ri and contents of register
Rj, and stores into Rj (Rj=Ri*Rj)
--------------------------------------------------------------------------
div Ri Rj stores into Rj the quotient of integer
division of contents register
Ri by the contents of register
Rj, and stores into Rj (Rj=Ri/Rj)
--------------------------------------------------------------------------
mod Ri Rj stores into Rj the rest of integer
division of contents of register
Ri by the contents of register
Rj, and stores into Rj (Rj=Ri%Rj)
--------------------------------------------------------------------------
zero Ri the contents of Ri becomes 0 (Ri=0)
--------------------------------------------------------------------------
inc Ri increments by 1 the contents of Ri
--------------------------------------------------------------------------
dec Ri decrements by 1 the contents of Ri
--------------------------------------------------------------------------
jump Addr jumps to instruction address Addr;
Addr can be a Label
--------------------------------------------------------------------------
jzero Ri Addr jumps to instruction address Addr,
if contents of Ri is zero;
Addr can be a Label
----------------------------------------------------------------------------
jnzero Ri Addr jumps to instruction address Addr,
if contents of Ri is different
from zero;
--------------------------------------------------------------------------
jpos Ri Addr jumps to instruction address Addr,
if contents of Ri is positiv;
Addr can be a Label
--------------------------------------------------------------------------
jneg Ri Addr jumps to instruction address Addr,
if contents of Ri is negativ
--------------------------------------------------------------------------
jsr Addr pushes the PC into the stack and
jumps to instruction address Addr
--------------------------------------------------------------------------
rtn pops an address from the stack
into the PC
--------------------------------------------------------------------------
push Ri pushes the contents of Ri into the
system stack
--------------------------------------------------------------------------
pop Ri pops at element from the system stack
into Ri
--------------------------------------------------------------------------
halt stops execution; Every program
must have this instruction in order
to end properly; otherwise an
'Out of Program' error will occur
Memory- mapped instructions
---------------------------
Apoo allows the configuration of a set of memory positions for special
purposes. The memory values and its functionality are given as a
parameter of the Apoo virtual machine. The default values allow the
simulation of input/output:
Memory Position Load/Store Meaning
----------------------------------------------------------------------
50000 load 50000 Ri loads 0 Ri
store Ri 50000 writes the character which ascii
code is Ri%256 in the Output
Window (in graphical interface)
or in stdout, in text mode.
------------------------------------------------------------------------
50001 load 50001 Ri reads an integer and stores it in Ri
store Ri 50001 writes the contents of Ri as an integer
-------------------------------------------------------------------------------
50010 load 50010 Ri loads 0 in Ri
store Ri 50010 writes a CR in the Output Window
(in graphical interface) or in
stdout, in text mode.
-------------------------------------------------------------------
(C) 1998-2006 Rogerio Reis, Nelma Moreira {rvr,nam}@ncc.up.pt
|
