Re: [Mspgcc-users] How2access SFRs via index?

[<Hel...@pr...>]

>> Is there a indexable way to access the SFRs?
>>
>> like: value = PxIN(5);
>> which should do the same like value = P5IN;

[ From: amx <amx@me...> - 2008-01-29 06:43 ]

> Try this macro:
> #define  PxIN(a)    P##a##IN

.. is a nice usage of the ## operator, but it does not work
for me because my 'a' is defined much later in a function
call at runtime:

   n = 5;
   printf( "PxIN(1)=%d.\n", PxIN(1) );
   printf( "PxIN(n)=%d.\n", PxIN(n) );

leads to:
   main.c:189: `PnIN' undeclared (first use in this function)


But good old '?' operator seems to do what i expect from him:

   printf( "PxIN(1)=%d.\n", PxIN(1) );
    12d6:   5f 42 20 00     mov.b   &0x0020,r15 ;0x0020
    12da:   7f f3           and.b   #-1,    r15 ;r3 As==11
    12dc:   0f 12           push    r15     ;
    12de:   30 12 0c 12     push    #4620       ;#0x120c
    12e2:   30 12 7e 22     push    #8830       ;#0x227e
    12e6:   b0 12 b6 70     call    #28854      ;#0x70b6
   printf( "PxIN(5)=%d.\n", PxIN(5) );
    12ea:   5f 42 30 00     mov.b   &0x0030,r15 ;0x0030
    12ee:   7f f3           and.b   #-1,    r15 ;r3 As==11
    12f0:   0f 12           push    r15     ;
    12f2:   30 12 19 12     push    #4633       ;#0x1219
    12f6:   30 12 7e 22     push    #8830       ;#0x227e
    12fa:   b0 12 b6 70     call    #28854      ;#0x70b6
   n = 3;
   printf( "PxIN(n)=%d.\n", PxIN(n) );
    12fe:   5f 42 18 00     mov.b   &0x0018,r15 ;0x0018
    1302:   7f f3           and.b   #-1,    r15 ;r3 As==11
    1304:   0f 12           push    r15     ;
    1306:   30 12 26 12     push    #4646       ;#0x1226
    130a:   30 12 7e 22     push    #8830       ;#0x227e
    130e:   b0 12 b6 70     call    #28854      ;#0x70b6

with PxIN(x) made like this:

#define PxIN(x)    ( (x) == 1 ? (P1IN) : \
                     (x) == 2 ? (P2IN) : \
                     (x) == 3 ? (P3IN) : \
                     (x) == 4 ? (P4IN) : \
                     (x) == 5 ? (P5IN) : \
                     (x) == 6 ? (P6IN) : 0 )

Haven't figured out a general solution for the default part '0'
esp. when it comes to PxOUT(x) stuff etc.


Ciao,
          Helmut

PS:
why?
wanted to have a single function to perform N pulses on any 
MSP430 portpin.
   void Impulse( byte portnr, byte pbit, word cnt ) { ... }
plus a
   #define  BLINK40(x)  (Impulse(4,0,x))
to have Port 4.0 pulse out some message with:
  BLINK40(5); 
  BLINK33(2);
etc.