ST20-C1 View Datasheet(PDF) - STMicroelectronics
Part Name
Description
MFG CO.
'ST20-C1' PDF : 205 Pages View PDF
addc
add with carry
Code: 21 F0
Description: Add Areg and Breg, unsigned, with carry propagation. This instruction
is provided for long arithmetic; address calculations may be performed with add, sub
and adc without affecting the carry flag.
Definition:
if (sum < 2BitsPerWord)
{
Areg′unsigned ←
Status′carry
←
}
else
{
Areg′unsigned ←
Status′carry
←
}
sum
clear
sum - 2BitsPerWord
set
Breg′ ← Creg
Creg′ ← Areg
where
sum = Aregunsigned + Bregunsigned + Statuscarry
– the value of sum is calculated to unlimited precision
Status Register:
Carry bit is set or cleared.
Comments:
Secondary instruction.
See also: adc add subc
section 4.4.
90/205
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