CLAMPS — Signed Clamp

Instruction Word

Slot
ae2_slot0
6
3
6
2
6
1
6
0
5
9
5
8
5
7
5
6
5
5
5
4
5
3
5
2
5
1
5
0
4
9
4
8
4
7
4
6
4
5
4
4
4
3
4
2
4
1
4
0
3
9
3
8
3
7
3
6
3
5
3
4
3
3
3
2
3
1
3
0
2
9
2
8
2
7
2
6
2
5
2
4
2
3
2
2
2
1
2
0
1
9
1
8
1
7
1
6
1
5
1
4
1
3
1
2
1
1
1
0
9876543210
Format ae_format2 - 64 bit(s)0000 1110
CLAMPS 1000000000001101 1110
r 3210
s 3210
t 3210

Slot
ae_slot0
6
3
6
2
6
1
6
0
5
9
5
8
5
7
5
6
5
5
5
4
5
3
5
2
5
1
5
0
4
9
4
8
4
7
4
6
4
5
4
4
4
3
4
2
4
1
4
0
3
9
3
8
3
7
3
6
3
5
3
4
3
3
3
2
3
1
3
0
2
9
2
8
2
7
2
6
2
5
2
4
2
3
2
2
2
1
2
0
1
9
1
8
1
7
1
6
1
5
1
4
1
3
1
2
1
1
1
0
9876543210
Format ae_format - 64 bit(s) 1111
CLAMPS 01011110
r 3210
s 3210
t 3210

Slot
Inst
6
3
6
2
6
1
6
0
5
9
5
8
5
7
5
6
5
5
5
4
5
3
5
2
5
1
5
0
4
9
4
8
4
7
4
6
4
5
4
4
4
3
4
2
4
1
4
0
3
9
3
8
3
7
3
6
3
5
3
4
3
3
3
2
3
1
3
0
2
9
2
8
2
7
2
6
2
5
2
4
2
3
2
2
2
1
2
0
1
9
1
8
1
7
1
6
1
5
1
4
1
3
1
2
1
1
1
0
9876543210
Format x24 - 24 bit(s) 0
CLAMPS 00110011 0000
r 3210
s 3210
t 3210

Slot
ae_slot0
6
3
6
2
6
1
6
0
5
9
5
8
5
7
5
6
5
5
5
4
5
3
5
2
5
1
5
0
4
9
4
8
4
7
4
6
4
5
4
4
4
3
4
2
4
1
4
0
3
9
3
8
3
7
3
6
3
5
3
4
3
3
3
2
3
1
3
0
2
9
2
8
2
7
2
6
2
5
2
4
2
3
2
2
2
1
2
0
1
9
1
8
1
7
1
6
1
5
1
4
1
3
1
2
1
1
1
0
9876543210
Format ae_format1 - 64 bit(s)1 1110
CLAMPS 01011110
r 3210
s 3210
t 3210

Assembler Syntax

CLAMPS ar, as, 7..22

C Syntax

#include <xtensa/tie/xt_misc.h>

extern int XT_CLAMPS(int s, immediate i);

Description

(please consult the Xtensa ® Instruction Set Architecture Reference Manual for any cross references and additional information)

CLAMPS tests whether the contents of address register as fits as a signed value of imm+1 bits (in the range 7 to 22). If so, the value is written to address register ar; if not, the largest value of imm+1 bits with the same sign as as is written to ar. Thus CLAMPS performs the function

y min(max(x, 2imm), 2imm1)

CLAMPS may be used in conjunction with instructions such as ADD, SUB, MUL16S, and so forth to implement saturating arithmetic.

Operation

sign ← AR[s]31
AR[r] ← if AR[s]30..t+7 = sign24-t
		then AR[s]
		else sign25-t||(not sign)t+7

Exceptions

EveryInstR Group (see EveryInstR Group:)

Implementation Pipeline

In Out
ars Estage arr Estage

Protos that use CLAMPS

proto CLAMPS { out int32 r, in int32 s, in immediate i }{}{
CLAMPS r, s, i + 0;
}