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

SUBS (register, asr, 32-bit)

Test 1: uops

Code:

  subs w0, w0, w1, asr #17
  mov x0, 1
  mov x1, 2

(no loop instructions)

1000 unrolls and 1 iteration

Retires: 1.000

Issues: 2.000

Integer unit issues: 2.001

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)
100420302001200110005226510001000200020011000
100420302001200110005226510001000200020011000
100420302001200110005226510001000200020011000
100420302001200110005226510001000200020011000
100420302001200110005226510001000200020011000
100420302001200110005226510001000200020011000
100420302001200110005226510001000200020011000
100420302001200110005226510001000200020011000
100420302001200110005226510001000200020011000
100420302001200110005226510001000200020011000

Test 2: Latency 1->2

Code:

  subs w0, w0, w1, asr #17
  mov x0, 1
  mov x1, 2

(fused SUBS/B.cc loop)

100 unrolls and 100 iterations

Result (median cycles for code): 2.0030

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)
10204200302010120101101045289721010510206202122000110100
10204200302010120101101045290871010410208202162000110100
10204200302010120101101045290871010410208202162000110100
10204200302010120101101045290871010410208202162000110100
10204200302010120101101045290871010410208202162000110100
10204200302010120101101045290871010410208202162000110100
10204200302010120101101045290871010410208202882001510100
10204200302010120101101045290871010410208202162000110100
10204200302010120101101045290871010410208202162000110100
10204200302010120101101045290871010410208202162000110100

1000 unrolls and 10 iterations

Result (median cycles for code): 2.0030

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)
10024200302002120021100255291171002010020200202001110010
10024200302002120021100205292491002010020200202001110010
10024200302002120021100205292491002010020200202001110010
10024200302002120021100205292491002010020200202001110010
10024200302002120021100205292491002010020200202001110010
10024200302002120021100205292491002010020200202001110010
10024200302002120021100205292491002010020200202001110010
10024200302002120021100205292491002010020200202001110010
10024200302002120021100205292491002010020200202001110010
10024200302002120021100205292491002010020200202001110010

Test 3: Latency 1->3

Code:

  subs w0, w1, w0, asr #17
  mov x0, 1
  mov x1, 2

(fused SUBS/B.cc loop)

100 unrolls and 100 iterations

Result (median cycles for code): 2.0030

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)
10204200302010120101001010405290011010410206202162000110100
10204200302010120101001010405290441010410206202162000110100
10204200302010120101001010405290871010410208202162000110100
10204200302010120101001010405290871010410208202162000110100
10204200302010120101001010405290871010410208202162000110100
10204200302010120101001010405290871010410208202162000110100
10204200302010120101001010405290871010410208202162000110100
10204202222018620186001024605290871010410208202162000110100
10204200302010120101001010405290871010410208202162000110100
10204200302010120101001010405290871010410208202162000110100

1000 unrolls and 10 iterations

Result (median cycles for code): 2.0030

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)
10024200302002120021100255292151002510030200202001110010
10024200302002120021100205292491002010020200202001110010
10024200302002120021100205292491002010020200202001110010
10024200302002120021100205292491002010020200202001110010
10024200302002120021100205292491002010020200202001110010
10024200302002120021100205292491002010020200202001110010
10024200302002120021100205292491002010020200202001110010
10024200302002120021100205292491002010020200442001110010
10024200302002120021100255292491002010020200202001110010
10024200302002120021100205292491002010020200202001110010

Test 4: Latency 4->2

Chain cycles: 1

Code:

  subs w0, w1, w2, asr #17
  cset x1, cc
  mov x0, 1
  mov x1, 2
  mov x2, 3
  mov x3, 4
  mov x4, 5

(fused SUBS/B.cc loop)

100 unrolls and 100 iterations

Result (median cycles for code, minus 1 chain cycle): 2.0030

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)
20204300303010130101201067892712010720214302153000120100
20204300303010130101201057893692010520212302183000120100
20204300303010130101201057893692010520212302183000120100
20204300303010130101201057896922014020254302183000120100
20204300303010130101201057893692010520212302183000120100
20204300303010130101201057893692010520212302183000120100
20204300303010130101201057893692010520212302183000120100
20204300303010130101201057893692010520212302183000120100
20204300303010130101201057893692010520212302183000120100
20204300303010130101201057897022014020252302183000120100

1000 unrolls and 10 iterations

Result (median cycles for code, minus 1 chain cycle): 2.0030

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)
20024300303001130011200157894592001520032300383000120010
20024300303001130011200157894592001520032300383000120010
20024300303001130011200157894592001520032300383000120010
20024300303001130011200157894592001520032300383000120010
20024300303001130011200157894592001520032300383000120010
20024300303001130011200157894592001520032300383000120010
20024300303001130011200157894592001520032300383000120010
20024300303001130011200157894592001520032300383000120010
20024300303001130011200157894592001520032300983001520010
20024300303001130011200157894592001520032300383000120010

Test 5: Latency 4->3

Chain cycles: 1

Code:

  subs w0, w1, w2, asr #17
  cset x2, cc
  mov x0, 1
  mov x1, 2
  mov x2, 3
  mov x3, 4
  mov x4, 5

(fused SUBS/B.cc loop)

100 unrolls and 100 iterations

Result (median cycles for code, minus 1 chain cycle): 2.0030

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)
20205300603011530115201407891052010620214302183000120100
20204300303010130101201057893692010520212302183000120100
20204301263014330143201827893692010520212302183000120100
20204300303010130101201057893692010520212302183000120100
20204300303010130101201057893692010520212302183000120100
20204300303010130101201057893692010520212302183000120100
20204301753016430164202197893692010520212302183000120100
20204300303010130101201057897002014120255302183000120100
20204300303010130101201057893692010520212302183000120100
20204300303010130101201057893692010520212302183000120100

1000 unrolls and 10 iterations

Result (median cycles for code, minus 1 chain cycle): 2.0030

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)
20024300303001130011200157892172001520032300203000120010
20024300303001130011200107894382001020020300203000120010
20024300303001130011200107894382001020020300203000120010
20024300303001130011200107894382001020020300203000120010
20024300303001130011200107894382001020020300203000120010
20024300303001130011200107894382001020020300203000120010
20024300303001130011200107894382001020020300203000120010
20024300303001130011200107894382001020020300203000120010
20024300303001130011200107894382001020020300203000120010
20024300303001130011200107894382001020020300203000120010

Test 6: throughput

Count: 8

Code:

  subs w0, w8, w9, asr #17
  subs w1, w8, w9, asr #17
  subs w2, w8, w9, asr #17
  subs w3, w8, w9, asr #17
  subs w4, w8, w9, asr #17
  subs w5, w8, w9, asr #17
  subs w6, w8, w9, asr #17
  subs w7, w8, w9, asr #17
  mov x8, 9
  mov x9, 10
  mov x10, 11

(fused SUBS/B.cc loop)

100 unrolls and 100 iterations

Result (median cycles for code divided by count): 0.6675

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)
8020453416160116160116801221099831801268022616024816001480100
8020453404160114160114801231099937801238022416024816001480100
8020453404160114160114801231100076801238022416024816001480100
8020553436160162160162801641099988801278022816024816001480100
8020453404160114160114801231100076801238022416024816001480100
8020453404160114160114801231100070801238022416024816001480100
8020453404160114160114801231100076801238022416024816001480100
8020453404160114160114801231100076801238022416024816001480100
8020453404160114160114801231114495801638026416024816001480100
8020453404160114160114801231100076801238022416024816001480100

1000 unrolls and 10 iterations

Result (median cycles for code divided by count): 0.6671

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)
8002453380160042160042800481107842800488004816002016001180010
8002453371160021160021800201107732800208002016002016001180010
8002453371160021160021800201107732800208002016002016001180010
8002553409160081160081800831107732800208002016002016001180010
8002453371160021160021800201106780800808008016002016001180010
8002453371160021160021800201107732800208002016002016001180010
8002553410160084160084800841107732800208002016002016001180010
8002453371160021160021800201108000800488004816007616003280010
8002453383160021160021800201107732800208002016002016001180010
8002453371160021160021800201107732800208002016002016001180010