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ZERO_REG
The two-byte zero register (ZERO_REG) is always equal to zero. It is useful as a fixed source of the
constant zero for comparisons and calculations. ZERO_REG can also be used as the WORD variable
in a long-indexed reference. This combination of register selection and address mode enables direct
addressing of any location in memory. A CMPL (compare long) instruction with ZERO_REG forces a
compare with a "generated" 32-bit zero value.
15
7
Bit
Number
15:0
Zero
This register is always equal to zero.
Zero (high byte)
Zero (low byte)
Function
REGISTERS
ZERO_REG
Address:
00H
Reset State:
0000H
8
0
C-91
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