At runtime the C++ language has the concept of Undefined Behavior. Under certain (well specified) conditions, the program has Undefined Behavior, that means that it can exhibit any behavior: it can crash, it can hang forever, it can print gibberish, it can appear to work, or it can do anything. A simplified explanation of why … Read more
Let’s look at the datasheet: http://atmel.com/dyn/resources/prod_documents/8271S.pdf As far as I can see, the ASR (arithmetic shift right) always shifts by one bit and cannot take the number of bits to shift; it takes one cycle to execute. Therefore, shifting right by n bits will take n cycles. Powers of two behave just the same as … Read more
After some searching through ancient asm source code archives of mine I found this for x86 MSDOS NASM platform I was using back in the days: ;.rnd ;al=rnd num <0,ah>; .rnd: pusha mov cx,ax .rnd0: mov bx,[cs:.rnddat] mov ax,[cs:.rndtim] xor al,bh add ah,bh rcr ax,3 xor al,bl rcl ax,2 .rnd2: cmp al,ch jbe .rnde sub … Read more
Converting this to C code doesn’t answer your actual question. A description of what the assembly is doing would be more helpful. The X and Z registers are actually two registers each, so they are two bytes long. Some instructions use the Z register as an address to the input. That is what is happening … Read more
uint8_t Values[4]={0}; uint8_t Loc=0; uint32_t Mask=0xFF; //32 bits UART Rx Buffer size for(uint8_t i=0;i<=24;i+=8) { Values[Loc]=(((Mask<<i) & UartRxBuf) >> i); Loc++; }