LPC1768_Strings_assembly code

Simulation is limited with Keil MDK, as it is impossible to simulate the behavior of the on-chip peripherals for more than 7500 devices supported today.

https://www.keil.com/support/docs/3726.htm

Beside, do always confirm the version of your product - in this case MDK -  in use.

At the moment MDK 5.31 is our latest release:

   http://www.keil.com/update/relnotes/MDK531.htm

I recommend to compare with this release.

The latest release of Keil MDK is always offered at:

   http://www2.keil.com/mdk5 

rkopsch said:

Simulation is limited

Nowadays, with the ready availability of low-cost hardware having on-chip debug, the usefulness of simulation is also limited!

shruthi84 - why not just run your code on real hardware using the debugger?

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.

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.

we are actually preparing some assignments for students to learn & work from home (COVID). Hence using the simulator.

Sir, I'm using MDK 5.31.

//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

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.