S3C84E5/C84E9/P84E9

INSTRUCTION SET

 

 

TM — Test under Mask

TMdst,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 the 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

Addr Mode

 

 

 

 

 

 

(Hex)

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 the working register R0 contains the value 0C7H (11000111B) and the 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.

 

6-85

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Samsung S3C84E5 user manual TM Test under Mask, TMdst,src, Operation dst and src