HP 3000 III Series Manual page 202

System Microcode
Table 5-4. Function Field Code Definitions (Continued)
I-~~-----------r-------I---------------------~--~-----------I
1 1
Field
1 1
I
Label and·Name
1
Code
1
Description
1
1 1 1 1
ROMI (Cont)
ROMN
(ROM And)
ROMX
(ROM Exclusive)
SUB
(Subtract)
SUBO
(Subtract-Enable
Over flow)
00011
00010
01111
01011
Register with RORI bits 16 thru 31.
The T-Bus then becomes the R-Bus
Register content inclusive "ored"
with the S-Bus Register content.
The R-Bus, Shift, Special, and Skip
Field Decoders are disabled by the
ROMI code.
The Function field code ROMN loads
the R-Bus Register wi th a l6-bit
constant obta ined fr om the microin-
struction. The ROMN code is decod-
ed from RORl, loading the R-Bus
Register with RORI bits 16 thru 31.
The T-Bus becomes the R-Bus Regist-
e r con te n t log i ca 11y "a n de d" wit h
the S-Bus Register content. The R-
Bus, Shift, Special, and Skip Field
Decoders are disabled by the ROMN
code.
The Function field code ROMX loads
the R-Bus Register with a l6-bit
constant obtained from the microin-
struction. The ROMX code is decod-
ed from RORl, loading the R-Bus
Register with RORI bits 16 thru 31.
The T-BllS becanes the R-Bus Regist-
er content exclusive "ored" with
the S-Bus Register content. The R-
Bus, Special, Shift, and Skip Field
Decoders are disabled by the ROMX
code.
The content of the S-Bus Register
is subtracted from the con tent of
the R-Bus Register and the result
is placed on the T-Bus.
The content of the S-Bus Register
is subtracted from the con tent of
the R-Bus Register and the result
is placed on the T-Bus. Carry and
overflow are modified in the Status
Register and condition code CCA is
set on the T-Bus data.
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