Is MSP430 internal flash write working well - msp430

Question

I am working on MSP430 and processing internal flash.
I have a doubt with MSP430 flash write lib.
In my opinion, with this implementation, the last byte might not be written in some cases.
This is function implementation.
void FlashCtl_write8(uint8_t *data_ptr,uint8_t *flash_ptr,uint16_t count){
//Clear Lock bit
HWREG16(FLASH_BASE + OFS_FCTL3) = FWKEY;
//Enable byte/word write mode
HWREG16(FLASH_BASE + OFS_FCTL1) = FWKEY + WRT;
while(count > 0)
{
//test busy
while(HWREG8(FLASH_BASE + OFS_FCTL3) & BUSY)
{
;
}
//Write to Flash
*flash_ptr++ = *data_ptr++;
count--;
}
//Clear WRT bit
HWREG16(FLASH_BASE + OFS_FCTL1) = FWKEY;
//Set LOCK bit
HWREG16(FLASH_BASE + OFS_FCTL3) = FWKEY + LOCK;
}
Is it a better solution if the function is implemented as below :
void FlashCtl_write8(uint8_t *data_ptr,uint8_t *flash_ptr,uint16_t count){
//Clear Lock bit
HWREG16(FLASH_BASE + OFS_FCTL3) = FWKEY;
//Enable byte/word write mode
HWREG16(FLASH_BASE + OFS_FCTL1) = FWKEY + WRT;
//test busy
while(HWREG8(FLASH_BASE + OFS_FCTL3) & BUSY)
{
;
}
while(count > 0)
{
//Write to Flash
*flash_ptr++ = *data_ptr++;
while(HWREG8(FLASH_BASE + OFS_FCTL3) & BUSY)
{
;
}
count--;
}
//Clear WRT bit
HWREG16(FLASH_BASE + OFS_FCTL1) = FWKEY;
//Set LOCK bit
HWREG16(FLASH_BASE + OFS_FCTL3) = FWKEY + LOCK;
}

Answer 1

Section 7.3.3.1 of the User's Guide says:
A byte or word write operation can be initiated from within flash memory or from RAM. When initiating from within flash memory, all timing is controlled by the flash controller, and the CPU is held while the write completes. After the write completes, the CPU resumes code execution with the instruction following
the write.
That code works because it is not actually necessary to check the BUSY bit.

Answer 2

As CL mentioned, as long as you run the code from flash, busywaiting is not necessary.
If, on the other hand, you would execute that code from RAM - for example, to dynamically rewrite the binary program code itself - you would need full locking.
The code below will do the same job. It is also slightly optimized for speed - no need to decrement another variable in the body of the loop.
void FlashCtl_write8(uint8_t *data_ptr, uint8_t *flash_ptr, uint16_t count)
{
const uint8_t *end = data_ptr + count;
// Clear Lock bit
HWREG16(FLASH_BASE + OFS_FCTL3) = FWKEY;
// Enable byte/word write mode
HWREG16(FLASH_BASE + OFS_FCTL1) = FWKEY + WRT;
while(data_ptr < end)
{
// Write to flash
*flash_ptr++ = *data_ptr++;
}
// Clear WRT bit
HWREG16(FLASH_BASE + OFS_FCTL1) = FWKEY;
// Set LOCK bit
HWREG16(FLASH_BASE + OFS_FCTL3) = FWKEY + LOCK;
}