Apple M1 Microarchitecture Research by Dougall Johnson

Firestorm: Overview | Base Instructions | SIMD and FP Instructions
Icestorm:  Overview | Base Instructions | SIMD and FP Instructions

FCVTL (vector, 4S)

Test 1: uops

Code:

  fcvtl v0.4s, v0.4h
  movi v0.16b, 1
  movi v1.16b, 2

(no loop instructions)

1000 unrolls and 1 iteration

Retires: 1.000

Issues: 1.000

Integer unit issues: 0.000

Load/store unit issues: 0.000

SIMD/FP unit issues: 1.000

retire (01)cycle (02)0304181e1f3f4e51inst issue (52)~issue fp/simd (54)~dispatch fp/simd (57)huge thing fp/simd (5b)696d6edispatch stall (70)scheduler rewind (75)scheduler stall (76)~dispatch op (78)~map op fp/simd (7e)~map lookup fp/simd (81)8283pipeline redirect (84)85inst all (8c)inst neon or fp (9a)a8accfd5d6ddinst fetch restart (de)e0? fp/simd (ee)f5f6f7f8fd
10043037221090612547251000100010003981603018303730372414328951000100010003037303711100110000073316112629100030383038303830383038
100430372201006125472510001000100039816030183037303724143289510001000100030373037111001100001873116112629100030383038303830383038
100430372300006762547251000100010003981603018303730372414328951000100010003037303711100110000073116112629100030383038303830383038
10043037230000612547251000100010003981603018303730372414328951000100010003037303711100110000073116112629100030383038303830383038
10043037220000612547251000100010003981603018303730372414328951000100010003037303711100110000073116112629100030383038303830383038
10043037230090612547251000100010003981603018303730372414328951000100010003037303711100110000073116112629100030383038303830383038
100430372300001032547251000100010003981603018303730372414328951000100010003037303711100110000073116112629100030383038303830383038
10043037240000612547251000100010003981603018303730372414328951000100010003037303711100110000073116112629100030383038303830383038
10043037290000612547251000100010003981603018303730372414328951000100010003037303711100110000073116112629100030383038303830383038
10043037220000612547251000100010003981603018303730372414328951000100010003037303711100110000073116112629100030383038303830383038

Test 2: Latency 1->2

Code:

  fcvtl v0.4s, v0.4h
  movi v0.16b, 1
  movi v1.16b, 2

(fused SUBS/B.cc loop)

100 unrolls and 100 iterations

Result (median cycles for code): 3.0037

retire (01)cycle (02)03080b18191e1f3a3f4e51inst issue (52)~issue int (53)~issue fp/simd (54)~dispatch int (56)~dispatch fp/simd (57)huge thing int (59)huge thing fp/simd (5b)60696d6edispatch stall (70)scheduler rewind (75)scheduler stall (76)~dispatch op (78)~map op int (7c)~map op fp/simd (7e)~map lookup int (7f)~map lookup fp/simd (81)8283pipeline redirect (84)85inst all (8c)inst branch (8d)inst branch taken (90)inst b.cc (94)inst integer (97)inst neon or fp (9a)9fa0a6a8a9acc2cfd5d6ddinst fetch restart (de)e0? int output thing (e9)? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
10204300372320000000612954725101001001000010010000500427716003001830037300372826432874510100200100002001000030037300371110201100991001001000010000003071011611296330100001003003830038300383003830038
10204300372330000000612954725101001001000010010000500427716003001830037300372826432874510100200100002001000030037300371110201100991001001000010000000071011611296330100001003003830038300383003830038
102043003723200000005002954725101001001000010010000500427716003001830037300372826432874510100200100002001000030037300371110201100991001001000010000000071011611296660100001003003830038300383003830038
10204300372330000000469295472510100100100001001000050042771600300183003730037282643287451010020010000200100003003730037111020110099100100100001000000102071011611296330100001003003830038300383003830038
10204300372330000000612954725101001001000010010000500427716003001830037300372826432874510100200100002001000030037300371110201100991001001000010000106071011611296330100001003003830038300383003830038
10204300372330000300612954725101001001000010010000500427716003001830037300372826432874510100200100002001000030037300371110201100991001001000010000103071011611296330100001003003830038300383008130038
102043003723200000006129547251010010010000100100005004277160030018300373003728264328745101002001000020010000300373003711102011009910010010000100000021071011611296330100001003003830038300383003830038
10204300372330000000612954725101001001000010010000500427716003001830037300372826432874510100200100002001000030037300371110201100991001001000010000002831071011612296330100001003003830038300383003830038
10204300372320000000612954725101001001000010010000500427716003001830037300372826432874510100200100002001000030037300371110201100991001001000010000003071011611296330100001003003830038300383003830038
102043003723300000001422954725101001001000010010000500427716003001830037300372826432874510100200100002001000030037300371110201100991001001000010000006071011611296330100001003003830038300383003830038

1000 unrolls and 10 iterations

Result (median cycles for code): 3.0037

retire (01)cycle (02)030b18191e1f3f4e51inst issue (52)~issue int (53)~issue fp/simd (54)~dispatch int (56)~dispatch fp/simd (57)huge thing int (59)huge thing fp/simd (5b)60696d6edispatch stall (70)scheduler rewind (75)scheduler stall (76)~dispatch op (78)~map op int (7c)~map op fp/simd (7e)~map lookup int (7f)~map lookup fp/simd (81)8283pipeline redirect (84)85inst all (8c)inst branch (8d)inst branch taken (90)inst b.cc (94)inst integer (97)inst neon or fp (9a)9fa0a1a6a7a8acc2c5cfd5d6ddinst fetch restart (de)e0? int output thing (e9)? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
1002430037242000006832952054100101310008121000050428256803001830084300372828632878710460201032422100003008530037211002110910101000010000001373006402162229629010000103003830038300383003830038
1002430037233000120612954725100101010000101000050427716003001830037300372828632876710010201016220100003003730037111002110910101000010000039406402162329629010000103003830038300383003830038
100243003724100012021512954725100101010000101000050427716003001830037300372828632876710010201000020100003003730037111002110910101000010020003006402162229629010000103003830038300383003830038
10024300372410000012429547251001010100001210150504277160030018301803003728286192876710010201000020100003003730037111002110910101000010000002840006402162329629010000103003830038300383003830038
10024300372320001770612954725100101410005101000050428106903001830084300372828632876710161201000020100123017930037111002110910101000010000000006402162329629010000103003830038300383003830038
100243003724100000612954725100101010000101000050427716003001830037300372828632876710010201000020100003003730037111002110910101000010000003006402162229629010000103003830038301803003830083
10024300372410009072629547251001010100001010000504277160130018300373003728286328767100102010000201000030037300371110021109101010000100000024016402162229686010000103003830038300383003830038
100243008424100000612954725100101010000101000050427716013001830037300372828632876710010201000020100003003730037111002110910101000010000009006402162229629010000103003830132300383003830038
10024300372421000027652954725100101010000101000050427716013001830037300372828632876710010201000020100003003730037111002110910101000010000009007272162229629010000103003830038300383003830038
100243003724300000582429475192100841810072151120081428932813034230464304172831641289371127328114613611444304163046110110021109101010000100220124945008503973229986310000103050730507305123051030511

Test 3: throughput

Count: 8

Code:

  fcvtl v0.4s, v8.4h
  fcvtl v1.4s, v8.4h
  fcvtl v2.4s, v8.4h
  fcvtl v3.4s, v8.4h
  fcvtl v4.4s, v8.4h
  fcvtl v5.4s, v8.4h
  fcvtl v6.4s, v8.4h
  fcvtl v7.4s, v8.4h
  movi v8.16b, 9

(fused SUBS/B.cc loop)

100 unrolls and 100 iterations

Result (median cycles for code divided by count): 0.2505

retire (01)cycle (02)030818191e3f51inst issue (52)~issue int (53)~issue fp/simd (54)~dispatch int (56)~dispatch fp/simd (57)huge thing int (59)huge thing fp/simd (5b)60696d6edispatch stall (70)scheduler rewind (75)scheduler stall (76)~dispatch op (78)~map op int (7c)~map op fp/simd (7e)~map lookup int (7f)~map lookup fp/simd (81)8283pipeline redirect (84)85inst all (8c)inst branch (8d)inst branch taken (90)inst b.cc (94)inst integer (97)inst neon or fp (9a)9fa0a1a6a8acc5branch mispredict (cb)cdcfd5d6ddinst fetch restart (de)e0? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
802042005915500005052580108100800081008002050064013212002020039200399977699908012020080032200800322003920039118020110099100100800001000000011151180161020036800001002004020040200402004020040
80204200391550000302580108100800081008002050064013202002020039200399977699908012020080032200800322003920039118020110099100100800001000000311151180160020036800001002004020040200402004020040
80204200391550000302580108100800081008002050064013212002020039200399977699908012020080032200800322003920039118020110099100100800001000000011151180160020036800001002004020040200402004020040
80204200391600000302580108100800081008002050064013212002020039200399977699908012020080032200800322003920039118020110099100100800001000000011151180160020036800001002004020040200402004020040
80204200391560000302580108100800081008002050064013212002020039200399977699908012020080032200800322003920039118020110099100100800001000001011151180160020036800001002004020040200402004020040
80204200391550000302580108100800081008002050064013202002020039200399977699908012020080032200800322003920039118020110099100100800001000000011151180160020036800001002004020040200402004020040
80204200391550000302580108100800081008002050064013202002020039200399977699908012020080032200800322003920039118020110099100100800001000000011151180160020036800001002004020040200402004020040
80204200391550000302580108100800081008002050064013202002020039200399977699908012020080032200800322003920039118020110099100100800001000003011151180160020036800001002004020040200402004020040
80204200391550000302580108100800081008012850064013202002020039200399977699908012020080032200800322003920039118020110099100100800001000003011151180160020036800001002004020040200402004020040
80204200391560000302580108100800081008002050064013212002020039200399977699908012020080032200800322003920039118020110099100100800001000000311151180160020036800001002004020040200402004020040

1000 unrolls and 10 iterations

Result (median cycles for code divided by count): 0.2505

retire (01)cycle (02)031e3f51inst issue (52)~issue int (53)~issue fp/simd (54)~dispatch int (56)~dispatch fp/simd (57)huge thing int (59)huge thing fp/simd (5b)60696d6edispatch stall (70)scheduler rewind (75)scheduler stall (76)~dispatch op (78)~map op int (7c)~map op fp/simd (7e)~map lookup int (7f)~map lookup fp/simd (81)8283pipeline redirect (84)85inst all (8c)inst branch (8d)inst branch taken (90)inst b.cc (94)inst integer (97)inst neon or fp (9a)9fa6a8a9acbranch mispredict (cb)cfd5d6d9ddinst fetch restart (de)e0? int output thing (e9)? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
800242003915504025800101080000108000050640000020020200392003999963100198001020800002080000200392003911800211091010800001000000502031602420036180000102004020040200402004020040
800242003915508225800101080000108000050640000020020200392003999963100198001020800002080000200392003911800211091010800001000000502031602620036080000102004020040200402004020040
800242003915604025800101080000108000050640000020020200392003999963100198001020800002080000200392003911800211091010800001001000502031605320036080000102004020040200402004020040
8002420039155124025800101080000108000050640000020020200392003999963100198001020800002080000200392003911800211091010800001001000502051603620036080000102004020040200402004020040
800242003915604025800101080000108000050640000020020200392003999963100198001020800002080000200392003911800211091010800001000000502031605620036080000102004020040200402004020040
800242003915504025800101080000108000050640000020020200392003999963100198001020800002080000200392003911800211091010800001007000502031603220036080000102004020040200402004020040
8002420039155040258001010800001080000506400000200202003920039100113100198001020800002080000200392003911800211091010800001000000502031602320036080000102004020040200402004020040
800242003915504025800101080000108000050640000020020200392003999963100198001020800002080000200392003911800211091010800001000000502061603320036080000102004020040200402004020040
800242003915504025800101080000108000050640000020020200392003999963100198001020800002080000200392003911800221091010800001000000502061603220036080000102004020040200402004020040
800242003915504025800101080000108000050640000020020200392003999963100198001020800002080000200392003911800211091010800001000000502031606620036080000102004020040200402004020040