Samsung KS57C2308 Manual page 113

KS57C2308/P2308/C2316/P2316
BTST
— Bit Test and Skip on True
BTST dst.b
Operation:
C
DA.b
mema.b
memb.@L
@H+DA.b
Description: The specified bit within the destination operand is tested. If it is "1", the instruction that
immediately follows the BTST instruction is skipped; otherwise the instruction following the BTST
instruction is executed. The destination bit value is not affected.
Operand
C
DA.b
mema.b
memb.@L
@H+DA.b
*
mema.b
Examples: 1. If RAM bit location 30H.2 is set to "0", the following instruction sequence will execute the RET
instruction:
BTST 30H.2
RET
JP
Operand
Test carry bit and skip if set (= "1")
Test specified bit and skip if memory bit is set
1 1 0
1 1 b1
a7 a6 a5
* 1 1 1
1 1 1
0 1 0
1 1 1
0 0 b1
1 0 b1
1 1 b1
LABEL2
Operation Summary
Binary Code
1 0 1 1
b0 0 0 1
a4 a3 a2 a1
1 1 0 0
1 1 0 0
0 a5 a4 a3
1 1 0 0
b0 a3 a2 a1
Second Byte
b0 a3 a2 a1
b0 a3 a2 a1
; If 30H.2 = "1", then skip
; If 30H.2 = "0", return
SAM47 INSTRUCTION SET
Bytes
Operation Notation
1 Skip if C = 1
1 Skip if DA.b = 1
a0
1 Skip if mema.b = 1
1 Skip if [memb.7–2 + L.3–2].
[L.1–0] = 1
a2
1 Skip if [H + DA.3–0].b = 1
a0
Bit Addresses
a0 FB0H–FBFH
a0 FF0H–FFFH
Cycles
1 1 + S
2 2 + S
2 2 + S
2 2 + S
2 2 + S
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