HP HP-16C - Section 4: Arithmetic and Bit Manipulation Functions; Square Root; Negative Numbers and Complementing

42 Section 4: Arithmetic and Bit Manipulation Functions
result of an addition is affected by the occurrence of a carry, and
the result of a subtraction is affected by the occurrence of a borrow.
If a carry out of the most significant bit occurs, 1 is added to the
result. If a borrow into the most significant bit occurs, 1 is
subtracted from the result. Both cases set flag 4.
([STATUS]: 1-04-1000)
Carry /1) No Carry
.y 1110 -3 1100
+(-1) +1110 + 3 +0011
-Z10 1100 —0,0 1111,
1
1101,
Borrow No Borrow
I 9,
3 2011 o 0110
-4 —0100 -5 —0101
—l5 1111 lo 0001,
— 1
1110,
The Carry Flag During Addition. The carry flag (flag 4, C
annunciator) will be set whenever a binary addition results in a
carry ‘“out of”’ the most significant bit. If an addition does not
result in such a carry, the carry flag is cleared. This is the same for
all complement modes.
([STATUS]: 2-04-1000)
Carry Set Carry Cleared
A 1010 c 0110
+(-4) +1100 y +0001
S0 0110, 7,0 0111,
(incorrect, so out-of-range
flag set also)