CODEWITHSUNDEEP
cassemblypicmicrochip
Mohamed ZIEDAN
Mohamed ZIEDAN

Reputation: 9

how to convert this part of code from assembly to C language

i have a problem converting assembly code for microchip pic into C language it is two parts first part is

movlw HIGH RevTable ; get MS byte of table

and the table is

RevTable
        retlw B’00000000’ ; invalid
        retlw B’00100001’ ; phase /6
        retlw B’00000110’ ; phase /4
        retlw B’00100100’ ; phase /5
        retlw B’00011000’ ; phase /2
        retlw B’00001001’ ; phase /1
        retlw B’00010010’ ; phase /3
        retlw B’00000000’ ; invalid

so what does that mean? i can not understand it

the second question is

incfsz ADC,w ; if ADC is 0xFF we’re at full speed - skip timer add

how it could be in the C thanks a lot

Upvotes: 0

Views: 1084

Answers (1)

GJ.
GJ.

Reputation: 10937

Your code sample is insufficient so I can't tell you all about:

movlw HIGH RevTable ; get MS byte of table

This is only a part of computed table jump. Your asm code must look something like:

movlw HIGH RevTable
movwf PCLATH            ;set high byte RevTable address
movf  TableIndex, w
movwf PCL               ;set low byte RevTable address this is computed table jump
;The return value is in wreg so one from RevTable table depend of TableIndex value

In c something like:

char RevTable[] = {'0','6','4','5','2','1','3','0'};

char TableIndex = 1;
char ValueFromTable;

ValueFromTable = RevTable[TableIndex] ;

The second part of code:

incfsz ADC,w ; if ADC is 0xFF we’re at full speed - skip timer add

Here is missing the second asm instruction which is executed or not depend of ADC value, something like:

 if (ADC != 255) ...

Upvotes: 4

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