Motorola 68000 assembly text strings

sadarax · 06-13-2008, 06:46 PM

I am writing an assembly program for the Motorola 68000, and I am having trouble doing dynamic strings. I want to be able to append information to a string, and then print it out.

EDIT: Made some progress. I can dynamically generate a string, but to append to that string is a problem. I am having trouble using the kludgey pointer system here in Assembler. I cannot seem to use pointers to the actual buffer....

Code:

goodbuffer  MACRO
            LEA     bufferptr,A1    ; Load pointer to string buffer
            LEA     \1,A2           ; Load the string starting address
            LEA     \2,A3           ; Load the string ending address
for_loop\@  CMPA    A2,A3           ; Check loop counters
            BEQ     loop_end\@      ; Check for ending loop
            MOVE.B  (A2),(A1)+      ; Move a character of string in A2 into the buffer
            ADDA    #1,A2           ; Increment the loop counter by 1
            BRA     for_loop\@      ; Loop again
loop_end\@
            LEA     bufferptr,A1    ; Reload original pointing address of bufferptr
            ADDA    A3,A1           ; Add ending string address to  bufferptr address
            MOVE.L A1,bufferptr     ; Store the new address into bufferptr
            ENDM

Here is an example in C++ of what to do in Assembly:

string str = "";
// doing stuff....
str += "ADDI.W ";
// more stuff....
str += " D2,D4";
cout << str << endl;
[/code]

Edit: Solved, though not efficiently.