## adc - add with carry

    dest = dest + source + CF

The adc instruction adds the source value (second operand) to the destination (either a register or a memory location) plus the carry flag.. The destination can be a 64, 32, 16 or 8 bit register or memory location. The source can be either a register, memory location or an immediate value. You can not use 2 memory addresses. You can add either 8, 16 or 32 bit immediate values to larger registers and the immediate value will be sign extended.

adc is designed to simplify adding large integers. In the code below a 256 bit sum is produced.

            mov     rax, [b]    ; get the low quadword of b, b[0]
            add     [a], rax    ; add b[0] to a[0]
            mov     rax, [b+8]  ; get the next quadword, b[1]
            adc     [a+8], rax  ; add the 2 quadwords + CF
            mov     rax, [b+16] ; get the next quadword, b[2]
            adc     [a+16], rax ; add the 2 quadwords + CF
            mov     rax, [b+24] ; get the next quadword, b[3]
            adc     [a+24], rax ; add the 2 quadwords + CF

### flags: OF SF ZF AF CF PF