Apple Microarchitecture Research by Dougall Johnson

M1/A14 P-core (Firestorm): Overview | Base Instructions | SIMD and FP Instructions
M1/A14 E-core (Icestorm):  Overview | Base Instructions | SIMD and FP Instructions

SXTB (64-bit)

Test 1: uops

Code:

  sxtb x0, x0
  mov x0, 1
  mov x1, 2

(no loop instructions)

1000 unrolls and 1 iteration

Retires: 1.000

Issues: 1.000

Integer unit issues: 1.001

Load/store unit issues: 0.000

SIMD/FP unit issues: 0.000

retire uop (01)cycle (02)schedule uop (52)schedule int uop (53)dispatch int uop (56)int uops in schedulers (59)dispatch uop (78)map int uop (7c)map int uop inputs (7f)? int output thing (e9)? int retires (ef)
100410301001100110002560310001000100010011000
100410301001100110002560310001000100010011000
100410301001100110002560310001000100010011000
100410301001100110002560310001000100010011000
100410301001100110002560310001000100010011000
100410301001100110002560310001000100010011000
100410301001100110002560310001000100010011000
100410301001100110002560310001000100010011000
100410301001100110002560310001000100010011000
100410301001100110002560310001000100010011000

Test 2: Latency 1->2

Code:

  sxtb x0, x0
  mov x0, 1
  mov x1, 2

(fused SUBS/B.cc loop)

100 unrolls and 100 iterations

Result (median cycles for code): 1.0030

retire uop (01)cycle (02)schedule uop (52)schedule int uop (53)dispatch int uop (56)int uops in schedulers (59)dispatch uop (78)map int uop (7c)map int uop inputs (7f)? int output thing (e9)? int retires (ef)
10204100301010110101101072593211010810216102121000110100
10204100301010110101101072594331010710214102141000110100
10204100301010110101101072595391010710212102121000110100
10204100301010110101101072595391010710212102121000110100
10204100301010110101101072595391010710212102121000110100
10204100301010110101101072595391010710212102121000110100
10204100301010110101101072595391010710212102121000110100
10204100301010110101101072595391010710212102121000110100
10204100301010110101101072595391010710212102121000110100
10204100301010110101101072595391010710212102121000110100

1000 unrolls and 10 iterations

Result (median cycles for code): 1.0030

retire uop (01)cycle (02)schedule uop (52)schedule int uop (53)dispatch int uop (56)int uops in schedulers (59)dispatch uop (78)map int uop (7c)map int uop inputs (7f)? int output thing (e9)? int retires (ef)
10024100301002110021100282594741002010020100201001110010
10024100301002110021100202595911002010020100201001110010
10024100301002110021100202595911002010020100201001110010
10024100301002110021100202595911002010020100201001110010
10025100601003510035100692595911002010020100201001110010
10024100301002110021100202595911002010020100201001110010
10024100301002110021100202595911002010020100201001110010
10024100301002110021100202595911002010020100201001110010
10024100301002110021100202595911002010020100201001110010
10024100301002110021100202595911002010020100201001110010

Test 3: throughput

Count: 8

Code:

  sxtb x0, x8
  sxtb x1, x8
  sxtb x2, x8
  sxtb x3, x8
  sxtb x4, x8
  sxtb x5, x8
  sxtb x6, x8
  sxtb x7, x8
  mov x8, 9

(fused SUBS/B.cc loop)

100 unrolls and 100 iterations

Result (median cycles for code divided by count): 0.3342

retire uop (01)cycle (02)schedule uop (52)schedule int uop (53)dispatch int uop (56)int uops in schedulers (59)dispatch uop (78)map int uop (7c)map int uop inputs (7f)? int output thing (e9)? int retires (ef)
80204268738011580115801202403608012080224802248001580100
80204267468011580115801202403608012080224802248001580100
80204267378011580115801202403608012080224802248001580100
80204267378011580115801202403608012080224802248001580100
80204267378011580115801202403608012080224802248001580100
80204267378011580115801202403608012080224802248001580100
80204267378011580115801202403608012080224802248001580100
80204267378011580115801202403608012080224802248001580100
80204267378011580115801202403608012080224802768005780100
80204267378011580115801202403608012080224802248001580100

1000 unrolls and 10 iterations

Result (median cycles for code divided by count): 0.3339

retire uop (01)cycle (02)schedule uop (52)schedule int uop (53)schedule simd uop (54)schedule ldst uop (55)dispatch int uop (56)dispatch simd uop (57)int uops in schedulers (59)dispatch uop (78)map int uop (7c)map int uop inputs (7f)? int output thing (e9)? int retires (ef)
80024279048003780037008004202614858004480048800208001180010
80024269438002180021008002002774048002080020800208001180010
80024267138002180021008002002774048002080020800208001180010
80024267158002180021008002002674848009780102800208001180010
80024267188002180021008002002774048002080020800208001180010
80025267568007980079008009502774048002080020800208001180010
80024267138002180021008002002644788009780103800208001180010
80024267138002180021008002002774048002080020800208001180010
80025267628008080080008009502774048002080020800208001180010
80024267138002180021008002002774048002080020801018007180010