IA2910A Datasheet, PDF (7/19 Pages) InnovASIC, Inc – Microprogram Controller

IA2910A
Microprogram Controller
Page 7 of 19
Preliminary Data Sheet
Instruction Set Description
Table 2
I(3:0) Mnemonic Name
Reg/cntr Fail
Fail
Pass
contents Y
Stack
Y
0
JZ
Jump Zero
X
0
CLEAR
0
1
CJS
Cond JSB PL X
PC
HOLD
D
2
JMAP
Jump Map
X
D
HOLD
D
3
CJP
Cond Jump PL X
PC
HOLD
D
4
PUSH
Push/cond LD X
PC
PUSH
PC
cntr
5
JSRP
Cond JSB R/PL X
R
PUSH
D
6
CJV
Cond Jump
X
PC
HOLD
D
Vector
7
JRP
Cond Jump
X
R
HOLD
D
R/PL
8
RFCT
Repeat Loop,
.NE. 0
F
HOLD
F
Cntr .NE. 0
=0
PC
POP
PC
9
RPCT
Repeat PL, cntr .NE. 0
D
HOLD
D
.NE. 0
=0
PC
HOLD
PC
10
CRTN
Cond RTN
X
PC
HOLD
F
11
CJPP
Cond Jump PL X
PC
HOLD
D
& POP
12
LDCT
LD Cntr &
X
PC
HOLD
PC
Continue
13
LOOP
Test End Loop X
F
HOLD
PC
14
CONT
Continue
X
PC
HOLD
PC
15
TWB
Three-Way
.NE. 0
F
HOLD
PC
Branch
=0
D
POP
PC
NOTE 1: If CCENn is LOW and CCn is HIGH, HOLD; ELSE LOAD.
X = Don’t Care
.NE. = Not equal
Pass
Stack
CLEAR
PUSH
HOLD
HOLD
PUSH
PUSH
HOLD
HOLD
HOLD
POP
HOLD
HOLD
POP
POP
HOLD
POP
HOLD
POP
POP
Reg/cntr
HOLD
HOLD
HOLD
HOLD
NOTE 1
HOLD
HOLD
HOLD
DEC
HOLD
DEC
HOLD
HOLD
HOLD
LOAD
HOLD
HOLD
DEC
HOLD
Enable
PL
PL
MAP
PL
PL
PL
VECT
PL
PL
PL
PL
PL
PL
PL
PL
PL
PL
PL
PL
IA2910A Instruction Set
The IA2910A provides sixteen instructions which select the address of the next microinstruction to
be executed. Four of the instructions are unconditional – their effect depends only on the
instruction. Ten of the instructions have an effect which is partially controlled by an external, data-
dependent condition. Three of the instructions have an effect which is partially controlled by the
contents of the internal register/counter. The instruction set is shown in Table 2. Examples of the
Instruction Execution are illustrated in Figure 2. In this discussion it is assumed that CIN is tied
HIGH.
In the ten conditional instructions, the result of the data-dependent test is applied to CCn. If the
CCn input is LOW, the test is considered to have been passed, and the action specified in the name
occurs; otherwise, the test has failed and an alternate (often simply the execution of the next
sequential microinstruction) occurs. Testing of CCn may be disabled for a specific microinstruction
by setting CCENn HIGH, which unconditionally forces the action specified in the name; that is, it
forces a pass. Other ways of using CCENn include (1) tying it HIGH, which is useful if no
microinstruction is data-dependent; (2) tying it LOW if data-dependent instructions are never
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