Hi I am beginning using STM32CUbe IDE and I ant to migrate a Keil uBision project where I have a code calling two ASM functions.

[HMero.1]

these are the functions

__asm void my_strcpy(const char *src, char *dst)

{

loop

   LDRB r2, [r0] ; Load byte into r2 from memory pointed to by r0 (src pointer)

ADDS r0, #1 ; Increment src pointer

   STRB r2, [r1] ; Store byte in r2 into memory pointed to by (dst pointer)

ADDS r1, #1 ; Increment dst pointer

   CMP  r2, #0 ; Was the byte 0?

   BNE  loop ; If not, repeat the loop

   BX  lr ; Else return from subroutine

}

__asm void my_capitalize(char *str)

{

cap_loop

   LDRB r1, [r0] ; Load byte into r1 from memory pointed to by r0 (str pointer)

CMP r1, #'a'-1 ; compare it with the character before 'a'

BLS cap_skip ; If byte is lower or same, then skip this byte

CMP r1, #'z' ; Compare it with the 'z' character

BHI cap_skip ; If it is higher, then skip this byte

SUBS r1,#32 ; Else subtract out difference to capitalize it

   STRB r1, [r0] ; Store the capitalized byte back in memory

cap_skip

ADDS r0, r0, #1 ; Increment str pointer

CMP  r1, #0 ; Was the byte 0?

   BNE  cap_loop ; If not, repeat the loop

   BX  lr ; Else return from subroutine

}

The GNU compiler doesnt accept these functions

Please can you tell how to change these functions?

Best regards and thanks in advance

Horacio Merovich

[Pavel A.]

Start by replacing this with standard C library functions, strcpy (or better strncpy) and strupr.

Optimize later, when the project is working.

-- pa

[HMero.1]

Thanks for your answer

This code is part of a ARM Assembler course so we dont want to use here the standard C library functions.

Best regards

[Tesla DeLorean]

Honestly I despair the state of post-secondary education... is there not someone qualified to lead the course?

/* GNU/GAS Assembler code added into startup.s */
 
/* extern void my_strcpy(const char *src, char *dst); note parameters backward compared to C */
 
 .section .text.my_strcpy
 .type my_strcpy, %function
 
my_strcpy:
 
loop:
 
 LDRB r2, [r0] /* Load byte into r2 from memory pointed to by r0 (src pointer) */
 ADD r0, #1 /* Increment src pointer */
 
 STRB r2, [r1] /* Store byte in r2 into memory pointed to by (dst pointer) */
 ADD r1, #1 /* Increment dst pointer */
 
 CMP r2, #0 /* Was the byte 0? */
 BNE loop /* If not, repeat the loop */
 
 BX lr /* Else return from subroutine */
 
.size my_strcpy, .-my_strcpy
 
 
/* extern void my_capitalize(char *str); */
 
 .section .text.my_capitalize
 .type my_capitalize, %function
 
my_capitalize:
 
cap_loop:
 
 LDRB r1, [r0] /* Load byte into r1 from memory pointed to by r0 (str pointer) */
 CMP r1, #'a'-1 /* compare it with the character before 'a' */
 BLS cap_skip /* If byte is lower or same, then skip this byte */
 
 CMP r1, #'z' /* Compare it with the 'z' character */
 BHI cap_skip /* If it is higher, then skip this byte */
 
 SUB r1,#32 /* Else subtract out difference to capitalize it */
 STRB r1, [r0] /* Store the capitalized byte back in memory */
 
cap_skip:
 
 ADD r0, r0, #1 /* Increment str pointer */
 CMP r1, #0 /* Was the byte 0? */
 BNE cap_loop /* If not, repeat the loop */
 
 BX lr /* Else return from subroutine */
 
.size my_capitalize, .-my_capitalize
 
/* ... */

[HMero.1]

Hi

Thanks for your contribution to improve our education.

Best regards

Horacio