bsl - 2024.2 English

Description

Shifts the contents of register rA_L by the amount specified in register rB and puts the result in register rD_L.

The mnemonic bsll sets the S bit (Side bit). If the S bit is set, the barrel shift is done to the left. The mnemonics bslrl and bslra clear the S bit and the shift is done to the right.

The mnemonic bslra will set the T bit (Type bit). If the T bit is set, the barrel shift performed is Arithmetical. The mnemonics bslrl and bslll clear the T bit and the shift performed is Logical.

Pseudocode

if S = 1 then
   (rDL) ← (rAL) << (rB)[26:31]
else
   if T = 1 then
      if ((rB)[26:31]) ≠ 0 then
         (rDL)[0:(rB)[26:31]-1] ← (rAL)[0]
         (rDL)[(rB)[26:31]:31] ← (rAL) >> (rB)[26:31]
      else
         (rDL) ← (rAL)
   else
      (rDL) ← (rAL) >> (rB)[26:31]

Registers Altered

• rD_L

Latency

• 1 cycle with C_AREA_OPTIMIZED=0 or 2
• 2 cycles with C_AREA_OPTIMIZED=1

Notes

• These instructions are optional. To use them, MicroBlaze has to be configured to use barrel shift instructions (C_USE_BARREL=1).