itest command

Synopsis

itest[.b | .w | .l | .q | .s] [*]<value1> <op> [*]<value2>

Description

The itest command is used to compare two values. The return value $? is set accordingly.

By default it is assumed that the values are 4 byte integers. By appending a postfix (.b, .w, .l, .q, .s) the size can be specified:

postfix	meaning
.b	1 byte integer
.w	2 byte integer
.l	4 byte integer
.q	8 byte integer (only available if CONFIG_PHYS_64BIT=y)
.s	string

value1, value2

values to compare. Numeric values are hexadecimal. If ‘*’ is prefixed a hexadecimal address is passed, which points to the value to be compared.

op

operator, see table

operator	meaning
-lt	less than
<	less than
-le	less or equal
<=	less or equal
-eq	equal
==	equal
-ne	not equal
!=	not equal
<>	not equal
-ge	greater or equal
>=	greater or equal
-gt	greater than
>	greater than

Examples

The itest command sets the result variable $? to true (0) or false (1):

=> itest 3 < 4; echo $?
0
=> itest 3 == 4; echo $?
1

This value can be used in the if command:

=> if itest 0x3002 < 0x4001; then echo true; else echo false; fi
true

Numbers will be truncated according to the postfix before comparing:

=> if itest.b 0x3002 < 0x4001; then echo true; else echo false; fi
false

Postfix .s causes a string compare. The string ‘0xa1234’ is alphabetically smaller than ‘0xb’.

=> if itest.s 0xa1234 < 0xb; then echo true; else echo false; fi true

A value prefixed by ‘*’ is a pointer to the value in memory.

=> mm 0x4000
00004000: 00000004 ?
00004004: 00000003 ? =>
=> if itest *0x4000 == 4; then echo true; else echo false; fi
true
=> if itest *0x4004 == 3; then echo true; else echo false; fi
true

Configuration

The command is only available if CONFIG_CMD_ITEST=y.

Return value

The return value $? is 0 (true) if the condition is true and 1 (false) otherwise.