Svenska ElektronikForumet

TomasL skrev:ASM är inget språk, utan ren maskinkod

TomasL skrev: ASM är en samling MNEONICS

TomasL skrev: i ASM, dvs maskinkod

4.2.1 Control Directives
Control directives control how code is assembled.
• #define – Define a Text Substitution Label.............................................. p. 68
• #include – Include Additional Source File .............................................. p. 92
• #undefine – Delete a Substitution Label................................................. p. 117
• constant – Declare Symbol Constant ..................................................... p. 60
• end – End Program Block.......................................................................... p. 71
• equ – Define an Assembler Constant ........................................................ p. 74
• org – Set Program Origin.......................................................................... p. 100
• processor – Set Processor Type ............................................................ p. 106
• radix – Specify Default Radix .................................................................. p. 106
• set – Define an Assembler Variable ......................................................... p. 109
• variable – Declare Symbol Variable....................................................... p. 118

4.2.2 Conditional Assembly Directives
Conditional assembly directives permit sections of conditionally assembled code.
These are not run-time instructions like their C language counterparts. They define
which code is assembled, not how the code executes.
• else – Begin Alternative Assembly Block to if Conditional..................... p. 71
• endif – End Conditional Assembly Block................................................. p. 72
• endw – End a while Loop ........................................................................ p. 73
• if – Begin Conditionally Assembled Code Block...................................... p. 88
• ifdef – Execute If Symbol has Been Defined.......................................... p. 90
• ifndef – Execute If Symbol has not Been Defined.................................. p. 91
• while – Perform Loop While Condition is True......................................... p. 119

4.2.3 Data Directives
Data directives control the allocation of memory and provide a way to refer to data
items symbolically, i.e., by meaningful names.
• __badram – Identify Unimplemented RAM............................................... p. 48
• __badrom – Identify Unimplemented ROM............................................... p. 49
• __config – Set Processor Configuration Bits .......................................... p. 58
• config – Set Processor Configuration Bits (PIC18 MCUs) ...................... p. 59
• __idlocs – Set Processor ID Locations .................................................. p. 87
• __maxram – Define Maximum RAM Location ........................................... p. 97
• __maxrom – Define Maximum ROM Location........................................... p. 98
• cblock – Define a Block of Constants ...................................................... p. 54
• da – Store Strings in Program Memory (PIC12/16 MCUs) ........................ p. 61
• data – Create Numeric and Text Data ...................................................... p. 62
• db – Declare Data of One Byte .................................................................. p. 65
• de – Declare EEPROM Data Byte ............................................................. p. 67
• dt – Define Table (PIC12/16 MCUs).......................................................... p. 70
• dw – Declare Data of One Word................................................................. p. 70
• endc – End an Automatic Constant Block ................................................. p. 72
• fill – Specify Program Memory Fill Value .............................................. p. 82
• res – Reserve Memory ............................................................................. p. 107

4.2.4 Listing Directives
Listing directives control the MPASM assembler listing file format. These directives
allow the specification of titles, pagination, and other listing control. Some listing
directives also control how code is assembled.
• error – Issue an Error Message...............................................................p. 74
• errorlevel – Set Message Level............................................................p. 76
• list – Listing Options ...............................................................................p. 93
• messg – Create User Defined Message.....................................................p. 98
• nolist – Turn off Listing Output ...............................................................p. 100
• page – Insert Listing Page Eject ................................................................p. 103
• space – Insert Blank Listing Lines.............................................................p. 110
• subtitle – Specify Program Subtitle .......................................................p. 110
• title – Specify Program Title...................................................................p. 111

4.2.5 Macro Directives
Macro directives control the execution and data allocation within macro body
definitions.
• endm – End a Macro Definition...................................................................p. 73
• exitm – Exit from a Macro.........................................................................p. 78
• expand – Expand Macro Listing ................................................................p. 80
• local – Declare Local Macro Variable ......................................................p. 94
• macro – Declare Macro Definition..............................................................p. 96
• noexpand – Turn off Macro Expansion......................................................p. 100

4.2.6 Object File Directives
Object file directives are used only when creating an object file.
• access_ovr – Begin an Object File Overlay Section in Access
RAM (PIC18 MCUs) ...................................................................................p. 56
• bankisel – Generate Indirect Bank Selecting Code (PIC12/16 MCUs)... p. 50
• banksel – Generate Bank Selecting Code ...............................................p. 52
• code – Begin an Object File Code Section ................................................p. 56
• code_pack – Begin an Object File Packed Code
• Section (PIC18 MCUs) ...............................................................................p. 65
• extern – Declare an Externally Defined Label .........................................p. 80
• global – Export a Label............................................................................p. 84
• idata – Begin an Object File Initialized Data Section ...............................p. 85
• idata_acs – Begin an Object File Initialized Data Section
• in Access RAM (PIC18 MCUs) ...................................................................p. 94
• pagesel – Generate Page Selecting Code (PIC10/12/16 MCUs) ............p. 103
• pageselw – Generate Page Selecting Code Using WREG Commands
(PIC10/12/16 MCUs) ..................................................................................p. 105
• udata – Begin an Object File Uninitialized Data Section...........................p. 111
• udata_acs – Begin an Object File Access Uninitialized Data
Section (PIC18 MCUs) ...............................................................................p. 120
• udata_ovr – Begin an Object File Overlaid Uninitialized Data Section....p. 114
• udata_shr – Begin an Object File Shared Uninitialized Data
Section (PIC12/16 MCUs) ..........................................................................p. 124

TABLE 3-4: ARITHMETIC OPERATORS AND PRECEDENCE
Operator Example
$         Current/Return program counter goto $ + 3
(         Left Parenthesis 1 + (d * 4)
)         Right Parenthesis (Length + 1) * 256
!         Item NOT (logical complement) if ! (a == b)
-         Negation (2’s complement) -1 * Length
~         Complement flags = ~flags
low(1)    Return low byte of address movlw low CTR_Table
high(1)   Return high byte of address movlw high CTR_Table
upper(1)  Return upper byte of address movlw upper CTR_Table
*         Multiply a = b * c
/         Divide a = b / c
%         Modulus entry_len = tot_len % 16
+         Add tot_len = entry_len * 8 + 1
-         Subtract entry_len = (tot - 1) / 8
<<        Left shift flags = flags << 1
>>        Right shift flags = flags >> 1
>=        Greater or equal if entry_idx >= num_entries
>         Greater than if entry_idx > num_entries
<         Less than if entry_idx < num_entries
<=        Less or equal if entry_idx <= num_entries
==        Equal to if entry_idx == num_entries
=         Not equal to if entry_idx != num_entries
&         Bitwise AND flags = flags & ERROR_BIT
^         Bitwise exclusive OR flags = flags ^ ERROR_BIT
|         Bitwise inclusive OR flags = flags | ERROR_BIT
&&        Logical AND if (len == 512) && (b == c)
||        Logical OR if (len == 512) || (b == c)
=         Set equal to entry_index = 0
+=        Add to, set equal entry_index += 1
-=        Subtract, set equal entry_index -= 1
*=        Multiply, set equal entry_index *= entry_length
/=        Divide, set equal entry_total /= entry_length
%=        Modulus, set equal entry_index %= 8
<<=       Left shift, set equal flags <<= 3
>>=       Right shift, set equal flags >>= 3
&=        AND, set equal flags &= ERROR_FLAG
|=        Inclusive OR, set equal flags |= ERROR_FLAG
^=        Exclusive OR, set equal flags ^= ERROR_FLAG
++        Increment(2) i ++
--        Decrement(2) i --

A series of instructions written by a programmer according to a given set of rules or conventions (“syntax”)

Programming languages, like human languages, are defined through the use of syntactic and semantic rules, to determine structure and meaning respectively.

A standard which specifies how (sort of) human readable text is run on a computer.

TomasL skrev:Har lagt upp The Quintessential PIC Microcontroller på min manualsida, det är en hyffsad bra "nybörjargenomgång" av PIC uC