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

CMN (uxth, 64-bit)

Test 1: uops

Code:

  cmn x0, w1, uxth
  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)
1004698200120011000146781000100020002001
1004698200120011000146781000100020002001
1004698200120011000146781000100020002001
1004698200120011000146781000100020002001
1004698200120011000146781000100020002001
1004698200120011000146781000100020002001
1004698200120011000146781000100020002001
1004698200120011000146781000100020002001
1004698200120011000146781000100020002001
1004698200120011000146781000100020002001

Test 2: Latency 3->1

Chain cycles: 1

Code:

  cmn x0, w1, uxth
  cset x0, cc
  mov x0, 1
  mov x1, 2

(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)
20204300303010130101201057892472010820214302153000110100
20204300303010130101201057893692010520212302183000110100
20204300303010130101201057893692010520212302183000110100
20204300303010130101201057893692010520212302183000110100
20204300303010130101201057893692010520212302183000110100
20204300303010130101201057893692010520212302183000110100
20204300303010130101201057893692010520212302183000110100
20204300303010130101201057893692010520212302183000110100
20204300303010130101201057893692010520212302183000110100
20204300303010130101201057893692010520212302843001510100

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)dispatch ldst uop (58)int uops in schedulers (59)simd uops in schedulers (5a)dispatch uop (78)map int uop (7c)map ldst uop (7d)map int uop inputs (7f)? int output thing (e9)? int retires (ef)
20024300303001130011200150789438020010200200300203000110010
20024300303001130011200100789438020010200200300203000110010
20024300303001130011200100789438020010200200300203000110010
20024300303001130011200100789438020010200200300203000110010
20024300303001130011200100789438020010200200300983001510010
20024300303001130011200100789438020010200200300203000110010
20024300303001130011200100789438020010200200300203000110010
20024300303001130011200100789438020010200200300203000110010
20024300303001130011200100789438020010200200300203000110010
20024300303001130011200100789438020010200200300203000110010

Test 3: Latency 3->2

Chain cycles: 1

Code:

  cmn x0, w1, uxth
  cset x1, cc
  mov x0, 1
  mov x1, 2

(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)
20204300303010130101201067892472010820214302153000110100
20205300603011530115201407893692010520212302183000110100
20204300303010130101201057893692010520212302183000110100
20204300303010130101201057893692010520212302183000110100
20204300303010130101201057893692010520212302183000110100
20204300303010130101201057893692010520212302183000110100
20204300303010130101201057893692010520212302183000110100
20204300303010130101201057893692010520212302183000110100
20204300303010130101201057893692010520212302183000110100
20204300303010130101201057893692010520212302183000110100

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)
20024300303001130011200157893812001520030300203000110010
20024300303001130011200107894382001020020300203000110010
20024300303001130011200107894382001020020300203000110010
20024300303001130011200107894382001020020300203000110010
20024300303001130011200107894382001020020300203000110010
20025300603002530025200517894382001020020300203000110010
20024300303001130011200107894382001020020300203000110010
20024300303001130011200107894382001020020300203000110010
20024300303001130011200107894382001020020300203000110010
20024300303001130011200107897902005120072300203000110010

Test 4: throughput

Count: 8

Code:

  cmn x0, w1, uxth
  cmn x0, w1, uxth
  cmn x0, w1, uxth
  cmn x0, w1, uxth
  cmn x0, w1, uxth
  cmn x0, w1, uxth
  cmn x0, w1, uxth
  cmn x0, w1, uxth
  mov x0, 1
  mov x1, 2

(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)
80204534041601171601178012711776018013080230160248160014100
80204534021601141601148012311776038012380224160248160014100
80205534351601631601638016911776318012380224160248160014100
80204534021601141601148012311776038012380224160248160014100
80204534021601141601148012311776278012380224160248160014100
80204534021601141601148012311776038012380224160248160014100
80204534021601141601148012311776278012380224160248160014100
80204534021601141601148012311776078012380224160248160014100
80204534021601141601148012311776278012380224160248160014100
80204534021601141601148012311776078012380224160248160014100

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)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)
8002453381160040160040008004801172240800468004616002016001110
8002453371160021160021008002001170032800208002016002016001110
8002453371160021160021008002001170032800208002016002016001110
8002453371160021160021008002001174364801758017516002016001110
8002453371160021160021008002001170032800208002016002016001110
8002453371160021160021008002001173325800578005716002016001110
8002453371160021160021008002001170032800208002016002016001110
8002453371160021160021008002001170032800208002016002016001110
8002453371160021160021008002001170032800208002016002016001110
8002453371160021160021008002001170032800208002016002016001110