SAM3X8E Atmel Corporation, SAM3X8E Datasheet - Page 123

• Manufacturer Part Number: SAM3X8E
• Manufacturer: Atmel Corporation

11.13.9
11.13.9.1
11.13.9.2
11.13.9.3
11.13.9.4
11.13.9.5
11057A–ATARM–17-Feb-12
11057A–ATARM–17-Feb-12
TST
TEQEQ
TST and TEQ
Syntax
Operation
Restrictions
Condition flags
Examples
R0, #0x3F8
R10, R9
Test bits and Test Equivalence.
where:
cond
Rn
Operand2
details of the options.
These instructions test the value in a register against Operand2. They update the condition flags
based on the result, but do not write the result to a register.
The TST instruction performs a bitwise AND operation on the value in Rn and the value of
Operand2. This is the same as the ANDS instruction, except that it discards the result.
To test whether a bit of Rn is 0 or 1, use the TST instruction with an Operand2 constant that has
that bit set to 1 and all other bits cleared to 0.
The TEQ instruction performs a bitwise Exclusive OR operation on the value in Rn and the value
of Operand2. This is the same as the EORS instruction, except that it discards the result.
Use the TEQ instruction to test if two values are equal without affecting the V or C flags.
TEQ is also useful for testing the sign of a value. After the comparison, the N flag is the logical
Exclusive OR of the sign bits of the two operands.
Do not use SP and do not use PC
These instructions:
• update the N and Z flags according to the result
• can update the C flag during the calculation of Operand2, see
• do not affect the V flag.
page 91
TST{cond} Rn, Operand2
TEQ{cond} Rn, Operand2
; Perform bitwise AND of R0 value to 0x3F8,
; APSR is updated but result is discarded
; Conditionally test if value in R10 is equal to
; value in R9, APSR is updated but result is discarded
is an optional condition code, see
is the register holding the first operand.
is a flexible second operand. See
.
“Conditional execution” on page
“Flexible second operand” on page 91
“Flexible second operand” on
SAM3X/A
SAM3X/A
96.
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for