Toggling bits
A bitwise XOR flips every bit that is set in the mask: a 1 in the mask inverts the corresponding bit of the value, a 0 leaves it alone. The immediate instruction is xori.
For example, XOR-ing n with 0x80 (decimal 128, bit 7) produces:
xori r3, r3, 128
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XOR is the bit-twiddler's toggle switch: applying the same mask twice returns the original value. Like ori, xori carries no dot and leaves the condition register alone.
The target below uses a different mask constant. Read the decimal immediate, convert it to find which bit(s) are toggled, and write the C expression.
xori r3, r3, 64
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Your task
Write toggle_bit to match the target.