This is simplified from a larger example.
In the C source, I have:
uint32_t xx = oxdeadbeef ;
I compiled with gcc -O or clang -O
Looking at ‘objdump -d a.out’ on the RPi 4, I see
9ac: 5297dde8 mov w8, #0xbeef // #48879
9b0: 72bbd5a8 movk w8, #0xdead, lsl #16
This produces the correct result, but, these are 16-bit values.
How do I force gcc or clang to use 32-bits in this case?
mov w8, #0xdeadbeef
Or, do I want to?
>Solution :
This micro does not have move immediate 32 value into the register, only 16 bits. 2 instructions are faster and shorter than storing the value in memory and load it into the register from memory.
That’s the reason why you have 2 instructions.