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Rev. 1.00, 05/04, page 25 of 544
Bit Bit Name
Initial
Value R/W Description
0 C Undefined R/W Carry Flag
Set to 1 when a carry occurs, and cleared to 0
otherwise. Used by
Add instructions, to indicate a carry
Subtract instructions, to indicate a borrow
Shift and rotate instructions, to indicate a carry
The carry flag is also used as a bit accumulator by bit
manipulation instructions.
2.4.5 Initial Register Values
The program counter (PC) among CPU internal registers is initialized when reset exception
handling loads a start address from a vector table. The trace (T) bit in EXR is cleared to 0, and the
interrupt mask (I) bits in CCR and EXR are set to 1. The other CCR bits and the general registers
are not initialized. Note that the stack pointer (ER7) is undefined. The stack pointer should
therefore be initialized by an MOV.L instruction executed immediately after a reset.