CCS/MSP430F5529: Question about subroutines

I have figured out how to use arrays that are already populated, but I am having trouble figuring out how to create an empty array in assembly and populate it in the way the problem specifies.

Hi Paul,

I would recommend that you start with the examples for 32 bit multiplication that can be found in the resource explorer:

https://dev.ti.com/tirex/explore/node?node=AH6hDdAJvU-xIH7K2W0L9g__IOGqZri__LATEST

If you're question is specific to how disassembly can be generated and viewed in Code Composer, I think this thread should help:

https://e2e.ti.com/support/microcontrollers/c2000/f/171/t/914424?tisearch=e2e-quicksearch&keymatch=Code%20Composer%20disassembly

BR,

Leo

Ah, thanks for the tip on generating disassembly.  I am failing to find any examples of creating an array and populating the individual elements with assembly language.  There are tons of examples of creating arrays with defined elements, but none on creating empty arrays to be populated or replacing elements in arrays (that I can find).  If there are any examples of this, or if one of you guys is slick enough to write some quick code to show how to do this, it would be greatly appreciated.  

The details vary with the particular assembler but you will define storage in the bss and then use those addresses. This is how I did it in gas:

        .section .bss
_tick:  .skip   2
rxqueue: .skip  QSIZE+4
txqueue: .skip  QSIZE+4

It is pretty basic assembly language stuff.

I'll just mention here that there's no C initialization, so if you put stuff in .bss it will start out with whatever's left over from your last program run.

As a matter of tactics, you might want to use an array initialized with e.g. -1.

Doesn't the C startup code zero out the entire bss?

I think the OP asked about an "assembly program", which wouldn't have C initialization.

Yeah, basically I want to take an array with 5 elements like array: 1, 2, 3, 4, 5 and then I want to have an integer value "b" that can be anything like 2 for example.  I am trying to make a subroutine that will do HW and SW (both) multiplication and return the array with power values: 2, 4, 8, 16, 32.  There aren't a lot of code examples I can find for this processor, however, so I figured I would ask the pros for help.  I figured out how to push the address of an initialized array with the number of elements, but the structure of the subroutine eludes me.

        .cdecls C,LIST,"msp430.h"       ; Include device header file

        .def    RESET                   ; Export program entry-point to
                                        ; make it known to linker.

		.text                           ; Assemble into program memory.
		.retain                         ; Override ELF conditional linking
        		                        ; and retain current section.
		.retainrefs                     ; And retain any sections that have
        		                        ; references to current section.
		.data
b:		.int 	2						; Create variable and initialize it to 2

RESET:  mov.w   #__STACK_END,SP         ; Initialize stack pointer
        mov.w   #WDTPW|WDTHOLD,&WDTCTL  ; Stop watchdog timer

;-------------------------------------------------------------------------------
; Main loop
;-------------------------------------------------------------------------------
main: 	mov.w	#b, R4
		push 	#arr 			;push the address of arr
 		push 	#5 				;push the number of elements
		sub.w 	#2, SP 			;allocate space for the product
		call 	#calc_power
		mov.w 	@SP, &P1OUT 	;store the product in P2OUT&P1OUT
		add.w 	#6, SP 			;collapse the stack

calc_power:

arr:	.int	1, 2, 3, 4, 5	;array initialization

;-------------------------------------------------------------------------------
; Stack Pointer definition
;-------------------------------------------------------------------------------
        .global __STACK_END
        .sect   .stack

;-------------------------------------------------------------------------------
; Interrupt Vectors
;-------------------------------------------------------------------------------
         .sect   ".reset"               ; MSP430 RESET Vector
         .short  RESET
         .end

I just realized I am going to have to use two arrays: one to populate with the results of the HW multiplier and one to populate with the results from the SW multiplier.