|Function||Add with Carry|
ADC[S] : Add with Carry
ADC will add two values and the Carry flag.
If the S bit is set (ADCS), the N and Z flags are set according to the result, and the C and V flags are set as follows: C if the result generated a carry (unsigned overflow); V if the result generated a signed overflow.
ADC is useful for multiword addition, for example adding two 64 bit values. Use ADD for basic addition.
ADC<suffix> <dest>, <op 1>, <op 2>
dest = op_1 + op_2 + Carry
If R0-R1 is a 64 bit value, and R2-R3 is another 64 bit value, the code below will add them, placing the result in R4-R5.
ADDS R4, R0, R2 ADC R5, R1, R3
The instruction bit pattern is as follows:
|31 - 28||27||26||25||24 - 21||20||19 - 16||15 - 12||11 - 0|
|condition||0||0||I||0 1 0 1||S||op_1||dest||op_2/shift|
Note: If the I bit is zero, and bits 4 and 7 are both one (with bits 5,6 zero), the instruction is UMLAL, not ADC.