Samsung C8249 Manual Do Utilizador

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INSTRUCTION SET                                   
S3C8245/P8245/C8249/P8249
6-86
TM
 
 
Test Under Mask
TM
dst,src
Operation:
dst  AND  src
This instruction tests selected bits in the destination operand for a logic zero value. The bits to be
tested are specified by setting a "1" bit in the corresponding position of the source operand (mask),
which is ANDed with the destination operand. The zero (Z) flag can then be checked to determine
the result. The destination and source operands are unaffected.
Flags:
C: Unaffected.
Z:
Set if the result is "0"; cleared otherwise.
S: Set if the result bit 7 is set; cleared otherwise.
V: Always reset to "0".
D: Unaffected.
H: Unaffected.
Format:
Bytes
Cycles
Opcode
(Hex)
Addr Mode
dst       src
opc
dst | src
2
4
72
r
r
6
73
r
lr
opc
src
dst
3
6
74
R
R
6
75
R
IR
opc
dst
src
3
6
76
R
IM
Examples:
Given:
R0  =  0C7H, R1  =  02H, R2  =  18H, register 00H  =  2BH, register 01H  =  02H, and
register 02H  =  23H:
TM
R0,R1
R0  =  0C7H, R1  =  02H, Z  =  "0"
TM
R0,@R1
R0  =  0C7H, R1  =  02H, register 02H  =  23H, Z  =  "0"
TM
00H,01H
Register 00H  =  2BH, register 01H  =  02H, Z  =  "0"
TM
00H,@01H
Register 00H  =  2BH, register 01H =  02H,
register 02H  =  23H, Z  =  "0"
TM
00H,#54H
Register 00H  =  2BH, Z  =  "1"
In the first example, if working register R0 contains the value 0C7H (11000111B) and register R1 the
value 02H (00000010B), the statement "TM  R0,R1" tests bit one in the destination register for a "0"
value. Because the mask value does not match the test bit, the Z flag is cleared to logic zero and
can be tested to determine the result of the TM operation.