Add/Subtract From/Negate instruction checks

[openpower-gitea-migrator]

Originally Gitea issue #11 by jfng (gitea) on 2022-04-11

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Add/Subtract From/Negate instruction checks

Instructions

D-form:

• addi
• addis
• addic
• addic.
• subfic

MLS:D-form:

• paddi

DX-form:

• addpcis

XO-form:

• add
• add.
• subf
• subf.
• addc
• addc.
• adde
• adde.
• subfc
• subfc.
• subfe
• subfe.
• addme
• addme.
• addze
• addze.
• subfme
• subfme.
• subfze
• subfze.
• neg
• neg.

Invalid forms

Prefixed Add:

• (R == 1) and (RA != 0)

GPR access

RA (read):

• D-form/MLS:D-form if (RA != 0)

RB (read):

• XO-form, except:
  • addme/addme.
  • addze/addze.
  • subfme/subfme.
  • subfze/subfze.
  • neg/neg.

RT (write):

• all

CR access

Write:

• '.' suffix (Rc=1)

SPR access

XER (read):

• 'e' suffix (Extended)

XER (write):

• 'c' suffix (Carrying)
• 'e' suffix (Extended)