5.11.7 Mask Directive

The .mask mask, offset directive provides MIPS-specific DWARF debugging information in the ELF file, but is not normally used with hand-written assembly source. It is useable with PIC32M devices and indicates which of the integer registers are saved in the current function's stack frame. The mask value is interpreted as a bitmask, with a bit in bit position n representing register number n. A bit set to 1 in the bitmask indicates that the corresponding register is saved. The registers are saved in a block located offset bytes from the canonical frame address (CFA), which is the value of the stack pointer on entry to the function.