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, 2 regs, 16B)

Test 1: uops

Code:

  st1 { v0.16b, v1.16b }, [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): 2.000

Issues: 3.000

Integer unit issues: 1.001

Load/store unit issues: 2.000

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)
6200529817300710032004100220003000800030002000500010012000
6200429584300110012000100020003000800030002000500010012000
6200429629300110012000100020003000800030002000500010012000
6200429824300110012000100020003000800030002000500010012000
6200429864300110012000100020003000800030002000500010012000
6200429646300110012000100020003000800030002000500010012000
6200429571300110012000100020003000800030002000500010012000
6200429583300110012000100020003000800030002000500010012000
6200429595300110012000100020003000800030002000500010012000
6200429589300110012000100020003000800030002000500010012000

Test 2: throughput

Count: 8

Code:

  st1 { v0.16b, v1.16b }, [x6], x8
  st1 { v0.16b, v1.16b }, [x6], x8
  st1 { v0.16b, v1.16b }, [x6], x8
  st1 { v0.16b, v1.16b }, [x6], x8
  st1 { v0.16b, v1.16b }, [x6], x8
  st1 { v0.16b, v1.16b }, [x6], x8
  st1 { v0.16b, v1.16b }, [x6], x8
  st1 { v0.16b, v1.16b }, [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): 2.0006

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)
1602051601462401428012416001880123160003280291271993224010620016001020040002080003160000100
1602041600452401038010316000080102160001280273272001024010320016000820040002080003160000100
1602041600452401038010316000080102160001280273272001024010320016000820040002080003160000100
1602041600452401038010316000080102160001280273272001024010320016000820040002080003160000100
1602041600452401038010316000080102160001280273272001024010320016000820040002080003160000100
1602041600452401038010316000080102160001280273272001024010320016000820040002080003160000100
1602041600452401038010316000080102160001280273272001024010320016000820040012080019160000100
1602041600452401038010316000080102160001280273272001024010320016000820040002080003160000100
1602041600452401038010316000080102160001280273272001024010320016000820040002080003160000100
1602041600452401038010316000080102160001280273272001024010320016000820040002080003160000100

1000 unrolls and 10 iterations

Result (median cycles for code divided by count): 2.0006

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)
1600251601472400518003316001880032160003280060271996824001620160010204001208001916000010
1600241600452400118001116000080010160000280041272000724001020160000204000008000116000010
1600241600452400118001116000080010160000280041272000724001020160000204000008000116000010
1600241600452400118001116000080010160000280041272000724001020160000204000008000116000010
1600241600452400118001116000080010160034280128272012024006420160048204000008000116000010
1600241600452400118001116000080010160000280041272000724001020160000204000008000116000010
1600241600452400118001116000080010160000280041272000724001020160000204000008000116000010
1600241600452400118001116000080010160000280041272000724001020160000204000008000116000010
1600251600732400468002916001780030160000280041272000724001020160000204000008000116000010
1600241600452400118001116000080010160000280041272000724001020160000204000008000116000010