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SSHL Shift Left With Saturation
3-232 Instruction Set SPRU733
Shift Left With Saturation
SSHL
Syntax SSHL (.unit) src2, src1, dst
.unit = .S1 or .S2
Compatibility C62x, C64x, C67x, and C67x+ CPU
Opcode
31 29 28 27 23 22 18 17 13 12 11 6 5 4 3 2 1 0
creg z dst src2 src1 x op 1 0 0 0 s p
3 1 5 5 5 1 6 1 1
Opcode map field used... For operand type... Unit Opfield
src2
src1
dst
xsint
uint
sint
.S1, .S2 10 0011
src2
src1
dst
xsint
ucst5
sint
.S1, .S2 10 0010
Description The src2 operand is shifted to the left by the src1 operand. The result is placed
in dst. When a register is used to specify the shift, the five least significant bits
specify the shift amount. Valid values are 0 through 31, and the result of the
shift is invalid if the shift amount is greater than 31. The result of the shift is
saturated to 32 bits. If a saturate occurs, the SAT bit in CSR is set one cycle
after dst is written.
Execution
if (cond) {
if ( bit(31) through bit(31−src1) of src2 are all 1s or all 0s)
dst = src2 << src1;
else if (src2 > 0)
saturate dst to 7FFF FFFFh;
else if (src2 < 0)
saturate dst to 8000 0000h;
}
else nop