SSAI — Set Shift Amount Immediate

Instruction Word

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
SSAI 010000000100 000 0000
sas 3210 4

Assembler Syntax

SSAI 0..31

C Syntax

#include <xtensa/tie/xt_core.h>

extern void XT_SSAI(immediate i);

Description

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

SSAI sets the shift amount register (SAR) to a constant. The shift amount sa field is split, with bits 3..0 in bits 11..8 of the instruction word, and bit 4 in bit 4 of the instruction word. Because immediate forms exist of most shifts (SLLI, SRLI, SRAI), this is primarily useful to set the shift amount for SRC.

Operation

SAR ← 0||sa

Exceptions

EveryInst Group (see EveryInst Group:)

Implementation Pipeline

In Out
SAR Estage

Protos that use SSAI

proto SSAI { in immediate i }{}{
SSAI i + 0;
}
proto SSAI_SRC { out int32 dst, in int32 src1, in int32 src2, in immediate amount }{}{
SSAI amount + 0;
SRC dst, src1, src2;
}