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156 Part 2 ½ Regions of Computer Space Section 1½ Microprogram-Based Processors


Table 3 Comparison of Am2901/Am2901 and Am2909/Am2910 Chips

Data/Memory

Am2901

Am2903

Technology

Low-power Schottky

Low-power Schottky

Minimum clock period

105 ns

80 ns

Organization

4-bit cascadable slice

4-bit cascadable slice

Pins

40

48

Microinstruction field length

9

11

Number of working registers

16

16
Expandable

Data-types supported

Boolean
2's complement integer

Boolean 2's complement integer
Unsigned integer
Sign/magnitude

Operators

3 arithmetic

Add
Subtract (2)

7 arithmetic

Add Add carry (4)
Subtract (2)

5 logic

OR
AND (2)
XOR
XNOR

9 logic

OR
AND (2)
XOR
XNOR NOR NAND Constant (2)

Logic shifts

Logic shifts
Arithmetic shifts
Sign extend
Special functions

Increment by 1 or 2
Unsigned multiply
2's complement multiply
2's complement divide
Single/double-length normalize
Sign/magnitude conversion to/from 2's complement

Status

Overflow
Zero
Carry-out

Overflow Zero Carry-out
Sign

Control

Am2909

Am2910

Technology

Low-power Schottky

Low-power Schottky

Typical delay

55 ns

35 ns

Organization

4-bit cascadable slice

12-bit, noncascadable

Pins

28

40

Address sources

External

External

4-deep stack

5-deep stack

Microprogram counter

Microprogram counter

Register

Register

Number of instructions

24

16

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