BSF (R64, R64) - Latency

Experiment 1 (with R9=0)

• Instruction: BSF R8, R9
• Code:

     0:	4d 0f bc c1          	bsf    r8,r9
  

• Init:

  MOV R9, 0

• Show nanoBench command
• Results:
  • Instructions retired: 1.0
  • Core cycles: 1.0
  • Reference cycles: 0.99
  • RS_UOPS_DISPATCHED: 2.0

Experiment 2 (with R9=1)

• Instruction: BSF R8, R9
• Code:

     0:	4d 0f bc c1          	bsf    r8,r9
  

• Init:

  MOV R9, 1

• Show nanoBench command
• Results:
  • Instructions retired: 1.0
  • Core cycles: 1.0
  • Reference cycles: 0.99
  • RS_UOPS_DISPATCHED: 2.0

Experiment 3 (with R9=2)

• Instruction: BSF R8, R9
• Code:

     0:	4d 0f bc c1          	bsf    r8,r9
  

• Init:

  MOV R9, 2

• Show nanoBench command
• Results:
  • Instructions retired: 1.0
  • Core cycles: 1.0
  • Reference cycles: 0.99
  • RS_UOPS_DISPATCHED: 2.0

Experiment 4 (with R9=0)

• Instruction: BSF R8, R9
• Chain instructions: MOVSX R8, R8D;MOVSX R8, R8D;MOVSX R8, R8D;MOVSX R8, R8D;MOVSX R8, R8D
• Chain latency: 5
• Code:

     0:	4d 0f bc c1          	bsf    r8,r9
     4:	4d 63 c0             	movsxd r8,r8d
     7:	4d 63 c0             	movsxd r8,r8d
     a:	4d 63 c0             	movsxd r8,r8d
     d:	4d 63 c0             	movsxd r8,r8d
    10:	4d 63 c0             	movsxd r8,r8d
  

• Init:

  MOV R9, 0

• Show nanoBench command
• Results:
  • Instructions retired: 6.0
  • Core cycles: 6.16
  • Reference cycles: 6.21
  • RS_UOPS_DISPATCHED: 7.0

Experiment 5 (with R9=1)

• Instruction: BSF R8, R9
• Chain instructions: MOVSX R8, R8D;MOVSX R8, R8D;MOVSX R8, R8D;MOVSX R8, R8D;MOVSX R8, R8D
• Chain latency: 5
• Code:

     0:	4d 0f bc c1          	bsf    r8,r9
     4:	4d 63 c0             	movsxd r8,r8d
     7:	4d 63 c0             	movsxd r8,r8d
     a:	4d 63 c0             	movsxd r8,r8d
     d:	4d 63 c0             	movsxd r8,r8d
    10:	4d 63 c0             	movsxd r8,r8d
  

• Init:

  MOV R9, 1

• Show nanoBench command
• Results:
  • Instructions retired: 6.0
  • Core cycles: 6.16
  • Reference cycles: 6.12
  • RS_UOPS_DISPATCHED: 7.0

Experiment 6 (with R9=2)

• Instruction: BSF R8, R9
• Chain instructions: MOVSX R8, R8D;MOVSX R8, R8D;MOVSX R8, R8D;MOVSX R8, R8D;MOVSX R8, R8D
• Chain latency: 5
• Code:

     0:	4d 0f bc c1          	bsf    r8,r9
     4:	4d 63 c0             	movsxd r8,r8d
     7:	4d 63 c0             	movsxd r8,r8d
     a:	4d 63 c0             	movsxd r8,r8d
     d:	4d 63 c0             	movsxd r8,r8d
    10:	4d 63 c0             	movsxd r8,r8d
  

• Init:

  MOV R9, 2

• Show nanoBench command
• Results:
  • Instructions retired: 6.0
  • Core cycles: 6.16
  • Reference cycles: 6.21
  • RS_UOPS_DISPATCHED: 7.0

Experiment 1 (with R9=0)

• Instruction: BSF R8, R9
• Chain instructions: CMOVZ R15, R15;MOVSX R8, R15D;MOVSX R8, R8D;MOVSX R8, R8D;MOVSX R8, R8D;MOVSX R8, R8D
• Chain latency: 7
• Code:

     0:	4d 0f bc c1          	bsf    r8,r9
     4:	4d 0f 44 ff          	cmove  r15,r15
     8:	4d 63 c7             	movsxd r8,r15d
     b:	4d 63 c0             	movsxd r8,r8d
     e:	4d 63 c0             	movsxd r8,r8d
    11:	4d 63 c0             	movsxd r8,r8d
    14:	4d 63 c0             	movsxd r8,r8d
  

• Init:

  MOV R9, 0

• Show nanoBench command
• Results:
  • Instructions retired: 7.0
  • Core cycles: 3.79
  • Reference cycles: 3.75
  • RS_UOPS_DISPATCHED: 9.0

Experiment 2 (with R9=1)

• Instruction: BSF R8, R9
• Chain instructions: CMOVZ R15, R15;MOVSX R8, R15D;MOVSX R8, R8D;MOVSX R8, R8D;MOVSX R8, R8D;MOVSX R8, R8D
• Chain latency: 7
• Code:

     0:	4d 0f bc c1          	bsf    r8,r9
     4:	4d 0f 44 ff          	cmove  r15,r15
     8:	4d 63 c7             	movsxd r8,r15d
     b:	4d 63 c0             	movsxd r8,r8d
     e:	4d 63 c0             	movsxd r8,r8d
    11:	4d 63 c0             	movsxd r8,r8d
    14:	4d 63 c0             	movsxd r8,r8d
  

• Init:

  MOV R9, 1

• Show nanoBench command
• Results:
  • Instructions retired: 7.0
  • Core cycles: 3.79
  • Reference cycles: 3.75
  • RS_UOPS_DISPATCHED: 9.0

Experiment 3 (with R9=2)

• Instruction: BSF R8, R9
• Chain instructions: CMOVZ R15, R15;MOVSX R8, R15D;MOVSX R8, R8D;MOVSX R8, R8D;MOVSX R8, R8D;MOVSX R8, R8D
• Chain latency: 7
• Code:

     0:	4d 0f bc c1          	bsf    r8,r9
     4:	4d 0f 44 ff          	cmove  r15,r15
     8:	4d 63 c7             	movsxd r8,r15d
     b:	4d 63 c0             	movsxd r8,r8d
     e:	4d 63 c0             	movsxd r8,r8d
    11:	4d 63 c0             	movsxd r8,r8d
    14:	4d 63 c0             	movsxd r8,r8d
  

• Init:

  MOV R9, 2

• Show nanoBench command
• Results:
  • Instructions retired: 7.0
  • Core cycles: 3.79
  • Reference cycles: 3.75
  • RS_UOPS_DISPATCHED: 9.0

Experiment 1

• Instruction: BSF R9, R8
• Chain instructions: MOVSX R8, R9D;MOVSX R8, R8D;MOVSX R8, R8D;MOVSX R8, R8D;MOVSX R8, R8D
• Chain latency: 5
• Code:

     0:	4d 0f bc c8          	bsf    r9,r8
     4:	4d 63 c1             	movsxd r8,r9d
     7:	4d 63 c0             	movsxd r8,r8d
     a:	4d 63 c0             	movsxd r8,r8d
     d:	4d 63 c0             	movsxd r8,r8d
    10:	4d 63 c0             	movsxd r8,r8d
  

• Show nanoBench command
• Results:
  • Instructions retired: 6.0
  • Core cycles: 7.0
  • Reference cycles: 6.99
  • RS_UOPS_DISPATCHED: 7.0

Experiment 1

• Instruction: BSF R9, R8
• Chain instructions: CMOVZ R15, R15;MOVSX R8, R15D;MOVSX R8, R8D;MOVSX R8, R8D;MOVSX R8, R8D;MOVSX R8, R8D
• Chain latency: 7
• Code:

     0:	4d 0f bc c8          	bsf    r9,r8
     4:	4d 0f 44 ff          	cmove  r15,r15
     8:	4d 63 c7             	movsxd r8,r15d
     b:	4d 63 c0             	movsxd r8,r8d
     e:	4d 63 c0             	movsxd r8,r8d
    11:	4d 63 c0             	movsxd r8,r8d
    14:	4d 63 c0             	movsxd r8,r8d
  

• Show nanoBench command
• Results:
  • Instructions retired: 7.0
  • Core cycles: 9.0
  • Reference cycles: 9.0
  • RS_UOPS_DISPATCHED: 9.0