Renesas H8S/2138 Series Manuel Page 17

  • Télécharger
  • Ajouter à mon manuel
  • Imprimer
  • Page
    / 148
  • Table des matières
  • MARQUE LIVRES
  • Noté. / 5. Basé sur avis des utilisateurs
Vue de la page 16
Microcomputer Technical Q&A
9
Q&A No.: QAH8S-008
Category: Instruction
Subject: SUBX Instruction
Question
Why is the Z flag value unchanged when the result of a SUBX (subtraction with carry) instruction
operation is 0?
Answer
This is because the SUBX instruction operation result is ANDed with the Z flag value before
execution of the instruction. The logical equation is shown below.
Z = Z' · Rm · Rm-1 ... · R0
When the execution result is 0, Rm · Rm-1 ... · R0 (abbreviated to Rn below) is 1. As the Z flag
value for this instruction is the AND of Rn and Z', when the execution result is 0, the Z flag value
is held.
Notes: m = 31 (longword size), 15 (word-size), or 8 (byte-size)
Ri = Bit I of result
Z' = Z flag value before instruction execution
Applicable Products
Applicability Series Applicability Series Applicability Series
Yes Entire H8S Series H8S/2655 H8S/2350
H8S/2355 H8S/2357 H8S/2345
H8S/2245 H8S/2148 H8S/2144
H8S/2138 H8S/2134 H8S/2128
H8S/2124
Vue de la page 16
1 2 ... 12 13 14 15 16 17 18 19 20 21 22 ... 147 148

Commentaires sur ces manuels

Pas de commentaire