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

SBC (64-bit)

Test 1: uops

Code:

  sbc x0, x0, x1
  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)
100410301001100110002560310001000300010011000
100410301001100110002560310001000300010011000
100410301001100110002560310001000300010011000
100410301001100110002560310001000300010011000
100410301001100110002560310001000300010011000
100410301001100110002560310001000300010011000
100410301001100110002560310001000300010011000
100410301001100110002560310001000300010011000
100410301001100110002560310001000300010011000
100410301001100110002560310001000300010011000

Test 2: Latency 1->2

Code:

  sbc x0, x0, x1
  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)
10204100301010110101101082593121010710214302421000110100
10204100301010110101101072595391010710212302361000110100
10204100301010110101101072595391010710212302361000110100
10204100301010110101101072595391010710212302361000110100
10204100301010110101101072595391010710212302361000110100
10204100301010110101101072595391010710212302361000110100
10204100301010110101101072595391010710212302361000110100
10204100301010110101101072595391010710212302361000110100
10204100301010110101101072595391010710212302361000110100
10204100301010110101101072595391010710212302361000110100

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)
10024100301002110021100282596281002810036300201001110010
10024100301002110021100202595911002010020300201001110010
10024100301002110021100202595911002010020300201001110010
10024100301002110021100202595911002010020300201001110010
10024100301002110021100202595911002010020300201001110010
10024100301002110021100202595911002010020300201001110010
10024100301002110021100202595911002010020300201001110010
10024100301002110021100202595911002010020300201001110010
10024100301002110021100202595911002010020300201001110010
10024100301002110021100202595911002010020300201001110010

Test 3: Latency 1->3

Code:

  sbc x0, x1, 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)
10204100301010110101101082593291010710214302421000110100
10204100301010110101101072595391010710212302361000110100
10204100301010110101101072595391010710212302361000110100
10204100301010110101101072595391010710212302361000110100
10204100301010110101101072595391010710212302361000110100
10204100301010110101101072595391010710212302361000110100
10204100301010110101101072595391010710212302361000110100
10204100301010110101101072595391010710212302361000110100
10204100301010110101101072595391010710212302361000110100
10204100301010110101101072595391010710212302361000110100

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)
10024100301002110021100292594741002010020300201001110010
10024100301002110021100202595911002010020300201001110010
10024100301002110021100202595911002010020300201001110010
10024100301002110021100202595911002010020300201001110010
10024100301002110021100202595911002010020300201001110010
10024100301002110021100202595911002010020300201001110010
10024100301002110021100202595911002010020300201001110010
10024100301002110021100202595911002010020300201001110010
10024100301002110021100202595911002010020300201001110010
10024100301002110021100202595911002010020300201001110010

Test 4: Latency 1->4

Chain cycles: 1

Code:

  sbc x0, x1, x2
  tst x0, 1
  mov x0, 1
  mov x1, 2
  mov x2, 3

(non-fused SUB/CBNZ loop)

100 unrolls and 100 iterations

Result (median cycles for code, minus 1 chain cycle): 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)
20204200302020120201202085191892020820216402322010110100
20204200302020120201202095194482020820216402322010110100
20204200302020120201202085194482020820216402322010110100
20204200302020120201202085194482020820216402322010110100
20204200302020120201202085194482020820216402322010110100
20204200302020120201202085194482020820216402322010110100
20204200302020120201202085194482020820216402322010110100
20204200302020120201202085194482020820216402322010110100
20204200302020120201202085194482020820216402322010110100
20204200302020120201202085194482020820216402322010110100

1000 unrolls and 10 iterations

Result (median cycles for code, minus 1 chain cycle): 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)
20024200302002120021200285196282002820036400522001110010
20024200302002120021200205195912002020020400202001110010
20024200302002120021200205195912002020020400202001110010
20024200302002120021200205195912002020020400202001110010
20024200302002120021200205195912002020020400202001110010
20024200302002120021200205195912002020020401402002510010
20024200302002120021200205195912002020020400202001110010
20024200302002120021200205195912002020020400202001110010
20024200302002120021200205195912002020020400202001110010
20024200302002120021200205195912002020020400202001110010

Test 5: throughput

Count: 8

Code:

  sbc x0, x8, x9
  sbc x1, x8, x9
  sbc x2, x8, x9
  sbc x3, x8, x9
  sbc x4, x8, x9
  sbc x5, x8, x9
  sbc x6, x8, x9
  sbc x7, x8, x9
  mov x8, 9
  mov x9, 10

(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)
802042687080115801158012029003280120802222402638001580100
802042675580115801158012029323680120802242402728001580100
802042673780115801158012029323680120802242402728001580100
802042673780115801158012029323680120802242402638001580100
802042673780115801158012029323680120802242402728001580100
802042673780115801158012029323680120802242402728001580100
802042673780115801158012029323680120802242402728001580100
802042673780115801158012029323680120802242402728001580100
802042673780115801158012029323680120802242402728001580100
802042674380115801158012029323680120802242402728001580100

1000 unrolls and 10 iterations

Result (median cycles for code divided by count): 0.3340

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)
800242789380038800388005435761180052800542400208001180010
800242679680021800218002042678080020800202400208001180010
800242673380021800218002042678080020800202400208001180010
800242672380021800218002038943780020800202400208001180010
800242673080021800218002042678080020800202400208001180010
800242672380021800218002042678080020800202400208001180010
800242672380021800218002042678080020800202400208001180010
800242672380021800218002042678080020800202400208001180010
800242672380021800218002042678080020800202400208001180010
800242672380021800218002042678080020800202400208001180010