Below is C code and asm representation for msp430F147.
Question:
1. Can anyone see reason why is push r2, and pop SR. Is it for fun?
2. has anyone found in early math lessons, that 144 = -112 !!!?
I fully understand, that 112+144 = 256. I also understand, that 2+2=4
But these are not what states in C.
Funny is that if constant is below 126 everything is OK.
casting to int doesn't help
I am used to write HW mul myself but after 1 year and many updates I thought
somebody has fixed it up.
t= usart0_rx_buffer[usart0_rx_extract_idx]*144;
mov #642, r13 ;#0x0282
mov &0x026c,r15 ;src addr 0x026c
add r13, r15 ;
push r2 ;
dint
nop
mov.b @r15, &0x0130 ;
mov.b #0, &0x0131 ;subst r3 with As==00
mov #-112, &0x0138 ;#0xff90
mov.b #0, &0x0139 ;subst r3 with As==00
mov &0x013a,r10 ;src addr 0x013a
pop SR
I have also suggestion to free(void* ptr) in malloc( which I am using for
ages. It helps me to free not only memory allocated via malloc, but also
pointers to memory in eeprom- which I directly use via pointer. I call free()
without worring if deallocation is possible. I also must mention, that
first int after __noinit_end is used to store value of memory size allocated
with malloc.(*t)
So if p is not withing malloc range no action is taken.
:
void myfree (void *p)
{
size_t *t = &__noinit_end;
if(((int)p < ((int)t +*t)) && ((int)p > (int)t)){
p--;
*t -= XSIZE(((size_t*)p));
MARK_FREE (((size_t*)p));
}
}
--
Pozdrowienia
Robert Seczkowski
[email protected]
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