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

LDURH

Test 1: uops

Code:

  ldurh w0, [x6, #1]
  mov x0, 1
  mov x1, 2
  mov x8, 0

(no loop instructions)

1000 unrolls and 1 iteration

Retires: 1.000

Issues: 1.000

Integer unit issues: 0.001

Load/store unit issues: 1.000

SIMD/FP unit issues: 0.000

retire uop (01)cycle (02)schedule uop (52)schedule int uop (53)schedule ldst uop (55)dispatch ldst uop (58)simd uops in schedulers (5a)dispatch uop (78)map ldst uop (7d)map ldst uop inputs (80)? int output thing (e9)? ldst retires (ed)
10057041027110261000816610001000100011000
10045501001110001000816610001000100011000
10045501001110001000867010001000100011000
10045551001110001000823810001000100011000
10045541001110001000823810001000100011000
10045541001110001000823810001000100011000
10045541001110001000823810001000100011000
10045541001110001000823810001000100011000
10045541001110001000823810001000100011000
10045541001110001000823810001000100011000

Test 2: Latency 1->2 (with chain penalty)

Chain cycles: 3

Code:

  ldurh w0, [x6, #1]
  eor x8, x8, x0
  eor x8, x8, x0
  add x6, x6, x8
  mov x0, 1
  mov x1, 2
  mov x8, 0

(fused SUBS/B.cc loop)

100 unrolls and 100 iterations

Result (median cycles for code, minus 3 chain cycles): 4.0042

retire uop (01)cycle (02)schedule uop (52)schedule int uop (53)schedule ldst uop (55)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)map ldst uop inputs (80)? int output thing (e9)? ldst retires (ed)? int retires (ef)
4020570336401083010710001301301001518596416940204015030251100176022410004300031000030100
4020470040401023010210000301031000318593926939934010630212100046022410004300021000030100
4020570117401103010810002301351000318594466940134010630212100046022410004300021000030100
4020470040401023010210000301031000318593926939934010630212100046022410004300021000030100
4020470040401023010210000301031000318593926939934010630212100046022410004300021000030100
4020470040401023010210000301031000318593926939934010630212100046022410004300021000030100
4020470040401023010210000301031000318593926939934010630212100046022410004300021000030100
4020470040401023010210000301031000318593926939934010630212100046022410004300021000030100
4020570070401103010810002301351000318593926939934010630212100046030210017300081000030100
4020470040401023010210000301031000318594196940034010630212100046022410004300021000030100

1000 unrolls and 10 iterations

Result (median cycles for code, minus 3 chain cycles): 4.0049

retire uop (01)cycle (02)schedule uop (52)schedule int uop (53)schedule ldst uop (55)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)map ldst uop inputs (80)? int output thing (e9)? ldst retires (ed)? int retires (ef)
4002570148400183001710001300401000318596236946934001630032100046002010000300031000030010
4002470047400133001310000300101000018596526947144001030020100006002010000300031000030010
4002470047400133001310000300101000018596526947144001030020100006002010000300031000030010
4002470047400133001310000300101000018596526947144001030020100006002010000300031000030010
4002470047400133001310000300101000018596526947144001030020100006002010000300031000030010
4002470047400133001310000300101000018596526947144001030020100006002010000300031000030010
4002470047400133001310000300101000018596526947144001030020100006002010000300031000030010
4002570134400233002110002300421000018597336947474001030020100006002010000300031000030010
4002470047400133001310000300101000018596526947144001030020100006002010000300031000030010
4002470047400133001310000300101000018596526947144001030020100006002010000300031000030010

Test 3: throughput

Count: 8

Code:

  ldurh w0, [x6, #1]
  ldurh w0, [x6, #1]
  ldurh w0, [x6, #1]
  ldurh w0, [x6, #1]
  ldurh w0, [x6, #1]
  ldurh w0, [x6, #1]
  ldurh w0, [x6, #1]
  ldurh w0, [x6, #1]
  mov x7, x6
  mov x8, x6
  mov x9, x6
  mov x10, x6
  mov x11, x6
  mov x12, x6
  mov x13, x6

(fused SUBS/B.cc loop)

100 unrolls and 100 iterations

Result (median cycles for code divided by count): 0.5006

retire uop (01)cycle (02)schedule uop (52)schedule int uop (53)schedule ldst uop (55)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)map ldst uop inputs (80)? int output thing (e9)? ldst retires (ed)? int retires (ef)
8020540181801231018002210080008300560390801082008001220080012180000100
8020440045801011018000010080008300480064801082008001220080012180000100
8020440045801011018000010080008300640070801082008001220080012180000100
8020440045801011018000010080008300640070801082008001220080012180000100
8020440045801011018000010080008300640070801082008001220080012180000100
8020440045801011018000010080008300640070801082008001220080069180000100
8020440045801011018000010080008300640070801082008001220080012180000100
8020440045801011018000010080008300640070801082008001220080012180000100
8020440045801011018000010080008300640070801082008001220080012180000100
8020540099801381018003710080008300640070801082008001220080012180000100

1000 unrolls and 10 iterations

Result (median cycles for code divided by count): 0.5007

retire uop (01)cycle (02)schedule uop (52)schedule int uop (53)schedule ldst uop (55)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)map ldst uop inputs (80)? int output thing (e9)? ldst retires (ed)? int retires (ef)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