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

ST1 (multiple, post-index, 1 reg, 4H)

Test 1: uops

Code:

  st1 { v0.4h }, [x6], x8
  nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop
  mov x0, 0
  mov x8, 0

(no loop instructions)

1000 unrolls and 1 iteration

Retires (minus 60 nops): 1.000

Issues: 2.000

Integer unit issues: 1.001

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 int uop (56)dispatch ldst uop (58)int uops in schedulers (59)simd uops in schedulers (5a)dispatch uop (78)map ldst uop (7d)map ldst uop inputs (80)? int output thing (e9)? ldst retires (ed)
6100529664200510031002100210003000400020001000300010011000
6100429045200110011000100010003000400020001000300010011000
6100429076200110011000100010003000400020001000300010011000
6100429074200110011000100010003000400020001000300010011000
6100429068200110011000100010003000400020001000300010011000
6100429074200110011000100010003000400020001000300010011000
6100429082200110011000100010003000400020001000300010011000
6100429017200110011000100010003000400020001000300010011000
6100429064200110011000100010003000400020001000300010011000
6100429043200110011000100010003000400020001000300010011000

Test 2: throughput

Count: 8

Code:

  st1 { v0.4h }, [x6], x8
  st1 { v0.4h }, [x6], x8
  st1 { v0.4h }, [x6], x8
  st1 { v0.4h }, [x6], x8
  st1 { v0.4h }, [x6], x8
  st1 { v0.4h }, [x6], x8
  st1 { v0.4h }, [x6], x8
  st1 { v0.4h }, [x6], x8
  mov x7, x6
  mov x8, x6
  mov x9, x6
  mov x10, x6
  mov x11, x6
  mov x12, x6
  mov x13, x6
  mov x8, 0

(fused SUBS/B.cc loop)

100 unrolls and 100 iterations

Result (median cycles for code divided by count): 1.0006

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)
80205801491601588014080018801438000310249431360026160109200800102002400248000480000100
8020480048160104801048000080104800023412311360107160106200800082002400248000480000100
8020480048160104801048000080104800023412311360107160106200800082002400248000480000100
8020480048160104801048000080104800023412311360107160106200800082002401538003380000100
8020480048160104801048000080104800023412311360107160106200800082002400248000480000100
8020480048160104801048000080104800023412311360107160106200800082002400248000480000100
8020480048160104801048000080104800023412311360107160106200800082002400248000480000100
8020480048160104801048000080104800014121301360102160105200800082002400248000480000100
8020480048160104801048000080104800023412311360107160106200800082002400248000480000100
8020480048160104801048000080104800014121301360102160105200800082002400248000480000100

1000 unrolls and 10 iterations

Result (median cycles for code divided by count): 1.0006

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)
8002580149160073800558001880056800038123341360057160019208001020240000800018000010
8002480048160011800118000080010800003405851360101160010208000020240000800018000010
8002480048160011800118000080010800003405851360101160010208000020240000800018000010
8002480048160011800118000080010800003405851360101160010208000020240144800338000010
8002480055160011800118000080010800003405851360101160010208000020240000800018000010
8002480055160011800118000080010800003405851360101160010208000020240000800018000010
8002480048160011800118000080010800003405851360101160010208000020240000800018000010
8002480048160011800118000080010800003405851360101160010208000020240000800018000010
8002480048160011800118000080010800003405851360101160010208000020240000800018000010
8002480048160011800118000080010800003405851360101160010208000020240000800018000010