New version of the documentation

docs/directives.rst

@@ -0,0 +1,92 @@
+Directives
+==========
+
+This section covers the directives supported by the simulator. Specifically,
+the simulator supports the following directives:
+
+* :ref:`directive-db`
+* :ref:`directive-dw`
+* :ref:`directive-org`
+* :ref:`directive-equ`
+
+.. _directive-db:
+
+DB: Define Byte 
+^^^^^^^^^^^^^^^
+
+This directive allows you to reserve memory space for *one byte* (8 bits). The
+receive directive receives two operands. Operand 1 sets the name or identifier
+assigned to the space. Operand 2 sets the initialization value of the reserved
+space. This operand can be a numeric value, a character or an array of
+characters. In the case of a single character, the initial value stored will
+correspond to the ASCII code of the character encoded in single quotes (``''``). In the
+case of an array, the values corresponding to the ASCII codes of those encoded
+between double quotes (``""```) will be encoded. If you want to encode a numeric value
+explicitly within the array, you must do it using the escape combination ``\x``.
+
++-----------------------------------+------------------------------------------------------------------+
+| Directive                         | Result                                                           |
++===================================+==================================================================+
+| ``DB var1, 0x01``                 | Reserseves one byte with an initial value of 0x01                |
++-----------------------------------+------------------------------------------------------------------+
+| ``DB char1, '1'``                 | Reserseves one byte with an initial value of 0x31                |
++-----------------------------------+------------------------------------------------------------------+
+| ``DB string, "Hello"``            | Reserseves five bytes with values {0x48, 0x65, 0x6C, 0x6C, 0x6F} |
++-----------------------------------+------------------------------------------------------------------+
+| ``DB string, "\x01\x02\x03\x04"`` | Reserseves four bytes with values {0x01, 0x02, 0x03, 0x04}       |
++-----------------------------------+------------------------------------------------------------------+
+
+.. _directive-dw:
+
+DW: Define Word
+^^^^^^^^^^^^^^^
+
+This directive allows you to reserve memory space for *two bytes* (16 bits). The
+receive directive receives two operands. Operand 1 sets the name or identifier
+assigned to the space. Operand 2 sets the initialization value of the reserved
+space. This operand can only be of numeric type.
+
++---------------------+-----------------------------------------------+
+| Directive           | Result                                        |
++============================+========================================+
+| ``DW var1, 2048``   | Reserseves two bytes with values {0x80, 0x00} |
++---------------------+-----------------------------------------------+
+| ``DW var2, 0x1FFF`` | Reserseves two bytes with values {0x1F, 0xFF} |
++---------------------+-----------------------------------------------+
+
+.. _directive-org:
+
+ORG: Advance Program Counter
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+This directive allows moving the program counter to a given address. The
+directive contains a single operand that sets the address from which subsequent
+instructions are to be encoded.
+
++-----------------+-------------------------------------------------------------------------+
+| Directive       | Result                                                                  |
++=================+=========================================================================+
+| ``ORG 0x100``   | The subsequent instructions will be encoded starting from address 0x100 |
++-----------------+-------------------------------------------------------------------------+
+
+
+.. _directive-equ:
+
+EQU: 8-bits bitwise AND 
+^^^^^^^^^^^^^^^^^^^^^^^^
+
+The EQU directive gives a symbolic name or tag to an expression. This tag can
+be later used in subsequent lines of assembly code and will be substituted by
+the value given. The directive receives two operands. The first sets the label
+or symbolic name. The second defines the expression by which occurrences of the
+label will be replaced in the code. These occurrences will only be evaluated in
+lines of code following the definition of the label.
+
++---------------------------+------------------------------------------------------------------+
+| Directive                 | Result                                                           |
++===========================+==================================================================+
+| ``EOS EQU 255``           | Any occurrence of ``EOS`` will be sustitued by ``255``           |
++---------------------------+------------------------------------------------------------------+
+| ``TMRPRELOAD EQU 0x0003`` | Any occurrence of ``TMRPRELOAD`` will be sustitued by ``0x0003`` |
++---------------------------+------------------------------------------------------------------+
+

docs/index.rst

@@ -33,4 +33,5 @@ The simulator has the following features:
 
     assembler
     instruction-set
+    directives
 

docs/instruction-set.rst

@@ -174,6 +174,9 @@ register. The integer contained by the register will be added to the value
 referenced by Operand 2. The result will be stored in the register referenced
 by Operand 1. 
 
+The operation will modify the values of the carry (C) and zero
+(Z) flags of the Status Register.
+
 +-----------+-------------------+-------------------+---------------------+
 | Opcode    | Operand 1         | Operand 2         | Example             |
 +===========+===================+===================+=====================+
@@ -191,11 +194,13 @@ by Operand 1.
 ADDB: 8-bits addition
 ^^^^^^^^^^^^^^^^^^^^^
 
-Performs an addition of two 8-bits integers. Every form of the instruction
-will have two operands. Operand 1 will always be a reference to an 8-bits
-register. The integer contained by the register will be added to the value
-referenced by Operand 2. The result will be stored in the register referenced
-by Operand 1.
+Performs an addition of two 8-bits integers. Every form of the instruction will
+have two operands. Operand 1 will always be a reference to an 8-bits register.
+The integer contained by the register will be added to the value referenced by
+Operand 2. The result will be stored in the register referenced by Operand 1.
+
+The operation will modify the values of the carry (C) and zero (Z) flags of the
+Status Register.
 
 +-----------+------------------+------------------+----------------------+
 | Opcode    | Operand 1        | Operand 2        | Example              |
@@ -986,6 +991,8 @@ operands.  Operand 1 will always be a reference to a 16-bits register. Operand
 2 will indicate the number of bit positions that the value shall be shifted.
 The result will be stored in the register referenced by Operand 1. 
 
+The operation will modify the values of the carry (C) and zero (Z) flags of the Status Register.
+
 +------------+-------------------+-------------------+---------------------+
 | Opcode     | Operand 1         | Operand 2         | Example             |
 +============+===================+===================+=====================+
@@ -1009,6 +1016,8 @@ operands.  Operand 1 will always be a reference to an 8-bits register. Operand
 2 will indicate the number of bit positions that the value shall be shifted.
 The result will be stored in the register referenced by Operand 1. 
 
+The operation will modify the values of the carry (C) and zero (Z) flags of the Status Register.
+
 +------------+------------------+------------------+---------------------+
 | Opcode     | Operand 1        | Operand 2        | Example             |
 +============+==================+==================+=====================+
@@ -1032,6 +1041,8 @@ operands.  Operand 1 will always be a reference to a 16-bits register. Operand
 2 will indicate the number of bit positions that the value shall be shifted.
 The result will be stored in the register referenced by Operand 1. 
 
+The operation will modify the values of the carry (C) and zero (Z) flags of the Status Register.
+
 +------------+-------------------+-------------------+---------------------+
 | Opcode     | Operand 1         | Operand 2         | Example             |
 +============+===================+===================+=====================+
@@ -1055,6 +1066,8 @@ operands.  Operand 1 will always be a reference to an 8-bits register. Operand
 2 will indicate the number of bit positions that the value shall be shifted.
 The result will be stored in the register referenced by Operand 1. 
 
+The operation will modify the values of the carry (C) and zero (Z) flags of the Status Register.
+
 +------------+------------------+------------------+---------------------+
 | Opcode     | Operand 1        | Operand 2        | Example             |
 +============+==================+==================+=====================+
@@ -1111,6 +1124,8 @@ register. The integer contained by the register will be substracted from the
 value referenced by Operand 2. The result will be stored in the register
 referenced by Operand 1. 
 
+The operation will modify the values of the carry (C) and zero (Z) flags of the Status Register.
+
 +-----------+-------------------+-------------------+---------------------+
 | Opcode    | Operand 1         | Operand 2         | Example             |
 +===========+===================+===================+=====================+
@@ -1134,6 +1149,8 @@ register. The integer contained by the register will be substracted from the
 value referenced by Operand 2. The result will be stored in the register
 referenced by Operand 1. 
 
+The operation will modify the values of the carry (C) and zero (Z) flags of the Status Register.
+
 +-----------+------------------+------------------+----------------------+
 | Opcode    | Operand 1        | Operand 2        | Example              |
 +===========+==================+==================+======================+