ARM Cortex-M4 - Absolute Value; Compare and Update Value

The Cortex-M4 Instruction Set
ARM DUI 0553A Copyright © 2010 ARM. All rights reserved. 3-20
ID121610 Non-Confidential
Example 3-1 shows the use of a conditional instruction to find the absolute value of a number.
R0 = abs ( R1 ).
Example 3-1 Absolute value
MOVS R0, R1 ; R0 = R1, setting flags
IT MI ; skipping next instruction if value 0 or positive
RSBMI R0, R0, #0 ; If negative, R0 = -R0
Example 3-2 shows the use of conditional instructions to update the value of R4 if the signed
values
R0 is greater than R1 and R2 is greater than R3 .
Example 3-2 Compare and update value
CMP R0, R1 ; Compare R0 and R1, setting flags
ITT GT ; Skip next two instructions unless GT condition holds
CMPGT R2, R3 ; If 'greater than', compare R2 and R3, setting flags
MOVGT R4, R5 ; If still 'greater than', do R4 = R5
VS V = 1 Overflow
VC V = 0 No overflow
HI C = 1 and Z = 0 Higher, unsigned
LS C = 0 or Z = 1 Lower or same, unsigned
GE N = V Greater than or equal, signed
LT N != V Less than, signed
GT Z = 0 and N = V Greater than, signed
LE Z = 1 and N != V Less than or equal, signed
AL Can have any value Always. This is the default when no suffix is specified.
Table 3-4 Condition code suffixes (continued)
Suffix Flags Meaning