Inline assembly queries [2]

[kernel mailz]

Hi,

Thanks for responding to my previous mail. A few more queries

a. What is the use of adding format specifiers in inline assembly
like
asm volatile("ld%U1%X1 %0,%1":"=r"(ret) : "m"(*ptr) : "memory");

b. using m or Z  with a memory address. I tried replacing m/Z but no change
Is there some guideline ?
gcc documentation says Z is obsolete. Is m/Z replaceable ?

- Manish