the absolute truth

The value register starts at -42, and the program should print its magnitude: 42.

Compare the register against zero, skip the sign flip when it is already positive, and flip it otherwise. negRd = -Rn (alias for `SUB Rd, ZR, Rn`). produces the negation of a register in one instruction.

Worth noticing once your solution passes: the same code must not damage a value that starts out positive. Change the starting value to 42 and run again to convince yourself.

what is checked

• the magnitude is printed on its own line
• the program exits cleanly
• the sign flip uses negRd = -Rn (alias for `SUB Rd, ZR, Rn`).