© MCS Electronics, 1995-2007
DECR
Action
Decrements a variable by one.
Syntax
DECR var
Remarks
There are often situations where you want a number to be decreased by 1. It is simpler to write :
DECR var compared to : var = var - 1
See also
INCR
Example
'----------------------------------------------------------------------------- |
|
------------ |
: decr.bas |
'name |
'copyright |
: (c) 1995-2005, MCS Electronics |
'purpose |
: demostrate decr |
'micro |
: Mega48 |
'suited for demo |
: yes |
'commercial addon needed |
: no |
'-----------------------------------------------------------------------------
------------
$regfile = "m48def.dat" |
' specify the used |
micro |
' used crystal |
$crystal = 4000000 |
frequency |
' use baud rate |
$baud = 19200 |
$hwstack = 32 |
' default use 32 |
for the hardware stack |
' default use 10 |
$swstack = 10 |
for the SW stack |
' default use 40 |
$framesize = 40 |
for the frame space |
|
Dim A As Byte , I As Integer |
|
A = 5 |
'assign value to a |
Decr A |
'decrease (by one) |
Print A |
'print it |
I = 1000 |
|
Decr I |
|
Print I |
|
End |
|
© MCS Electronics, 1995-2007
DECLARE FUNCTION
Action
Declares a user function.
Syntax
DECLARE FUNCTION TEST[( [BYREF/BYVAL] var as type)] As type
Remarks
test |
Name of the function. |
Var |
Name of the variable(s). |
Type |
Type of the variable(s) and of the result. Byte,Word, Integer, Long, |
|
Single or String. Bits are not supported. |
|
|
When BYREF or BYVAL is not provided, the parameter will be passed by reference. Use BYREF to pass a variable by reference with its address.
Use BYVAL to pass a copy of the variable.
See the CALL statement for more details.
You must declare each function before writing the function or calling the function. And the declaration must match the function.
Bits are global and can not be passed with functions or subs.
When you want to pass a string, you pass it with it's name : string. So the size is not important. For example :
Declare function Test(s as string, byval z as string) as byte
See also
CALL, SUB
Example
'----------------------------------------------------------------------------- |
|
------------ |
: function.bas |
'name |
'copyright |
: (c) 1995-2005, MCS Electronics |
'purpose |
: demonstration of user function |
'micro |
: Mega48 |
'suited for demo |
: yes |
'commercial addon needed |
: no |
'-----------------------------------------------------------------------------
------------
$regfile = "m48def.dat" |
' specify the used |
micro |
' used crystal |
$crystal = 4000000 |
frequency |
' use baud rate |
$baud = 19200 |
$hwstack = 32 |
' default use 32 |
|
© MCS Electronics, 1995-2007 |
for the hardware stack |
' default use 10 |
$swstack = 10 |
for the SW stack |
' default use 40 |
$framesize = 40 |
for the frame space |
|
'A user function must be declare before it can be used. 'A function must return a type
Declare Function Myfunction(byval I As Integer , S As String) As Integer
'The byval paramter will pass the parameter by value so the original value 'will not be changed by the function
Dim K As Integer Dim Z As String * 10 Dim T As Integer
'assign the values K = 5
Z = "123"
T = Myfunction(k , Z)
Print T
End
Function Myfunction(byval I As Integer , S As String) As Integer
'you can use local variables in subs and functions
Local P As Integer
P = I
'because I is passed by value, altering will not change the original 'variable named k
I = 10
P = Val(s) + I
'finally assign result
'Note that the same data type must be used !
'So when declared as an Integer function, the result can only be 'assigned with an Integer in this case.
Myfunction = P
End Function
DECLARE SUB
Action
Declares a subroutine.
Syntax
DECLARE SUB TEST[( [BYREF/BYVAL] var as type)]
Remarks
test |
Name of the procedure. |
Var |
Name of the variable(s). |
Type |
Type of the variable(s). Byte, Word, Integer, Long, Single or String. |
|
|
© MCS Electronics, 1995-2007
When BYREF or BYVAL is not provided, the parameter will be passed by reference. Use BYREF to pass a variable by reference with its address.
Use BYVAL to pass a copy of the variable.
See the CALL statement for more details.
You must declare each function before writing the function or calling the function. And the declaration must match the function.
Bits are global and can not be passed with functions or subs.
See also
CALL, SUB , FUNCTION
Example
'----------------------------------------------------------------------------- |
|
------------ |
: declare.bas |
'name |
'copyright |
: (c) 1995-2005, MCS Electronics |
'purpose |
: demonstrate using declare |
'micro |
: Mega48 |
'suited for demo |
: yes |
'commercial addon needed |
: no |
' Note that the usage of SUBS works different in BASCOM-8051 |
'----------------------------------------------------------------------------- |
|
------------ |
|
$regfile = "m48def.dat" |
' specify the used |
micro |
' used crystal |
$crystal = 4000000 |
frequency |
' use baud rate |
$baud = 19200 |
$hwstack = 32 |
' default use 32 |
for the hardware stack |
' default use 10 |
$swstack = 10 |
for the SW stack |
' default use 40 |
$framesize = 40 |
for the frame space |
|
' First the SUB programs must be declared
'Try a SUB without parameters
Declare Sub Test2
'SUB with variable that can not be changed(A) and
'a variable that can be changed(B1), by the sub program
'When BYVAL is specified, the value is passed to the subprogram
'When BYREF is specified or nothing is specified, the address is passed to 'the subprogram
Declare Sub Test(byval A As Byte , B1 As Byte) Declare Sub Testarray(byval A As Byte , B1 As Byte) 'All variable types that can be passed
'Notice that BIT variables can not be passed. 'BIT variables are GLOBAL to the application
Declare Sub Testvar(b As Byte , I As Integer , W As Word , L As Long , S As String)
'passing string arrays needs a different syntax because the length of the
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