UPD17134A Datasheet, PDF (243/292 Pages) NEC – 4-BIT SINGLE-CHIP MICROCONTROLLER

CHAPTER 19 INSTRUCTION SET
<3> Example
To jump to XYZ, if the asddress 1FH contents are 1 and the address 1EH contents are 3; otherwise,
jump to ABC.
To compare 8-bit data, this instruction is used in the following combination:
3
1EH
0011
1
1FH
0001
MEM01E
MEM01F
MEM
MEM
SKNE
SKE
BR
BR
0.1EH
0.1FH
MEM01F, #01H
MEM01E, #03H
ABC
XYZ
The above program can be rewritten as follows, using compare and zero flags:
MEM01E MEM
0.1EH
MEM01F MEM
0.1FH
SET2
CMP, Z
; CMP flag ← 1, Z flag ← 1
SUB
MEM01F, #01H
SUBC MEM01E, #03H
SKT1
Z
BR
ABC
BR
XYZ
(3) SKGE m, #n4
Skip if data memory greater than or equal to immediate data
<1> OP code
10
87
43
0
11001
mR
mc
n4
<2> Function
(m) –n4, skip if not borrow
Skips the next one instruction, if the data memory contents are greater than or equal to the immediate
data value (Executes as NOP instruction).
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