• State Accepted Answer
  • +1 person also asked this people also asked this
  • Locked Locked
  • Replies 9 replies
  • Subscribers 24 subscribers
  • Views 3708 views
  • Users 0 members are here
2025 survey

We are running a survey to help us improve the experience for all of our members. If you see the survey appear, please take the time to tell us about your experience if you can.

Options
Related
How was your experience today?
This discussion has been locked.
You can no longer post new replies to this discussion. If you have a question you can start a new discussion

LPC1768_Strings_assembly code

shruthi84

Hi, I'm working with LPC1768 MC & using the MDK simulator.  My assembly code is  involving strings. When I declare the string in data segment, it doesnt get reflected in memory window during the debug session. But if I declare the string in code segment, it gets reflected in the memory window during the debug session. Can anyone let me know, why this is happening?

Parents
  • 0

    Can you show an example? A picture or some code showing how you declare/define the strings that work and those that don't?

    Simulating an LPC1768 in Keil MDK 5.31 seems to work just fine: strings defined as constant data, on the stack, or on the heap show up in the debugger as strings.

Reply
  • 0

    Can you show an example? A picture or some code showing how you declare/define the strings that work and those that don't?

    Simulating an LPC1768 in Keil MDK 5.31 seems to work just fine: strings defined as constant data, on the stack, or on the heap show up in the debugger as strings.

Children
  • +1 in reply to Adam Lins

    Thanks for replying. Here are the code examples.

    For the simple code below the ascii value of the string appears in the memory window. Here the string is declared after the code.

             AREA data1, DATA
    ADD1 EQU 0x1000000

           AREA prog, CODE
          ENTRY
          EXPORT __main2
    __main2
            LDR R1, = ADD1
            LDR R2, =string
            LDRB R3, [R2]
      stop B stop
            string DCB "abcd"
         END

    But for the code below the ascii value does not appear in the memory window. Here the string is declared separately in data segment.

    AREA data1, DATA
    string DCB "abcd"

    ALIGN

    ADD1 EQU 0x1000000

           AREA prog, CODE
          ENTRY
          EXPORT __main2
    __main2
            LDR R1, = ADD1
            LDR R2, =string
            LDRB R3, [R2]
      stop B stop      
         END

    Please let me know the reason behind this issue.

  • 0 in reply to Andy Neil 

    //Example of string being declared in code segment.
    AREA data1, DATA
ADD1 EQU 0x1000000

	AREA prog, CODE
		ENTRY
	EXPORT __main2
__main2
		LDR R1, = ADD1
		LDR R2, =string
		LDRB R3, [R2]
stop    B stop
string DCB "abcd"
		END
    //Example of code being declared in Code segment
    AREA data1, DATA
ADD1 EQU 0x1000000
string DCB "abcd"
	AREA prog, CODE
		ENTRY
	EXPORT __main2
__main2
		LDR R1, = ADD1
		LDR R2, =string
		LDRB R3, [R2]
stop    B stop

		END

  • 0 in reply to shruthi84

    I suspect that your memory window configuration is what's causing the issue. If I set the address of the memory window to r2 (which will take the value of register r2), then I see the correct strings when I step through the functions. I modified your code a little to make each function C callable, to better work with my existing project. For example, when stepping through the code, I see the following (once r2 has been set):

    Note also that if you want to define a C string you need to add the NULL terminator, e.g.,

    string DCB "c string",0

    This is explained in the armasm User Guide.