Apple M1 Microarchitecture Research by Dougall Johnson

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

FCVTZU (scalar, fixed-point, S to S)

Test 1: uops

Code:

  fcvtzu s0, s0, #3
  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)031e3f4e51inst issue (52)~issue fp/simd (54)~dispatch fp/simd (57)huge thing fp/simd (5b)60696d6edispatch 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
100430372306125472510001000100039816013018303730372414328951000100010003037303711100110000073116112629100030383038303830383038
100430372306125472510001000100039816013018303730372414328951000100010003037303711100110000073116112629100030383038303830383038
100430372406125472510001000100039816013018303730372414328951000100010003037303711100110000073116112629100030383038303830383038
1004303724126125472510001000100039816013018303730372414328951000100010003037303711100110000373116112629100030383038303830383038
100430372406125472510001000100039816013018303730372414328951000100010003037303711100110000073116112629100030383038303830383038
100430372406125472510001000100039816013018303730372414328951000100010003037303711100110000073116112629100030383038303830383038
100430372306125472510001000100039816013018303730372414328951000100010003037303711100110000073116112629100030383038303830383038
100430372306125472510001000100039816013018303730372414328951000100010003037303711100110000073116112629100030383038303830383038
100430372306125472510001000100039816013018303730372414328951000100010003037303711100110000073116112629100030383038303830383038
100430372306125472510001000100039816013018303731212414328951000100010003037303711100110000073116112629100030383038303830383038

Test 2: Latency 1->2

Code:

  fcvtzu s0, s0, #3
  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)031e1f3f4e51inst 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)72scheduler 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)9fa0a1a8a9accfd5d6ddinst fetch restart (de)e0? int output thing (e9)? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
102043003723200612954725101001001000010010000500427716013001830037300372826403287451010020010000200100003003730037111020110099100100100001000000071001611296330100001003003830038300383003830038
102043003723300612954725101001001000010010600500427716003001830037300372826403287451010020010000200100003003730037111020110099100100100001000000671011611296330100001003003830038300383003830038
1020430037233006129547251010010010000100100005004277160030018300373003728264032874510100200100002001000030037300371110201100991001001000010000001271011611296330100001003003830038300383003830038
1020430037233006129547251010010010000100100005004277160030018300373003728264032874510100200100002001000030037300371110201100991001001000010000008471011611296330100001003003830038300383003830038
102043003723200182529547251010010010000100100005004277160130018300373003728264032874510100200100002001000030037300371110201100991001001000010000006071011611296330100001003003830038300383003830038
10204300372320057829547251010010010000100100005004277160130018300373003728264032874510100200100002001000030037300371110201100991001001000010000440071011611296330100001003003830038300383003830038
10204300372330010329547251010010010000100100005004277160130018300853003728264032874510100200100002001000030037300371110201100991001001000010000400071011611296330100001003003830038300383003830038
1020430037233008929547251010010010000100100005004277160030018300373003728264032874510100200100002001000030037300371110201100991001001000010000350071011611296330100001003003830038300383003830038
1020430037232006129547251010010010000100100005004277160030018300373003728264032874510100200100002001000030037300371110201100991001001000010000410071011611296330100001003003830038300383003830038
1020430037233006129547251010010010000100100005004277160130018300373003728264032874510100200100002001000030037300371110201100991001001000010000370071011611296330100001003003830038300383003830038

1000 unrolls and 10 iterations

Result (median cycles for code): 3.0037

retire (01)cycle (02)031e3f4e51inst 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)6061696d6edispatch 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)9fa0a8accdcfd0icache miss (d3)d5d6ddinst fetch restart (de)e0? int output thing (e9)? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
1002430037233061295479610048101000010100005042771600030018300373003728286328767100102010000201000030037300371110021109101010000100000640002162229629010000103003830038300383003830038
1002430037232061295472510010101000010100005042771600030018300373003728286328767100102010000201000030037300371110021109101010000100000640002162229629010000103003830038300383003830038
1002430037233061295472510010101000010100005042771600030018300373003728286328767100102010000201000030037300371110021109101010000100000640002162229629010000103003830038300383003830038
1002430037233081295472510010101000010100005042771600030018300373003728286328767100102010000201000030037300371110021109101010000100100640002162229629010000103003830038300383003830038
1002430037233061295472510010101000010100005042771600030018300373003728286328767100102010000201000030037300371110021109101010000100000640002162229629010000103003830038300383003830038
1002430037233061295472510010101000010100005042812160030018300373003728286328767100102010000201000030037300371110021109101010000100000640002162229629010000103003830038300383003830038
1002430037232061295472510010101000010100005042771600030018300373003728286328767100102010000201000030037300371110021109101010000100000640002162229629010000103003830038300383003830038
1002430037233061295472510010101000010100005042771600030018300373003728286328767100102010000201000030037300371110021109101010000100000640002162229629010000103003830038300383003830038
1002430037232061295472510010101000010100005042771600030018300373003728286328767100102010000201000030037300371110021109101010000100000640002162229629010000103008530038300383003830038
1002430037233961295472510010101000010100005042771600030018300373003728286328767100102010000201000030037300371110021109101010000100000640002162229629010000103003830038300383003830038

Test 3: throughput

Count: 8

Code:

  fcvtzu s0, s8, #3
  fcvtzu s1, s8, #3
  fcvtzu s2, s8, #3
  fcvtzu s3, s8, #3
  fcvtzu s4, s8, #3
  fcvtzu s5, s8, #3
  fcvtzu s6, s8, #3
  fcvtzu s7, s8, #3
  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)0318191e3a3f51inst 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)9fa0a8a9acc5branch mispredict (cb)cdcfd5d6ddinst fetch restart (de)e0? int output thing (e9)? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
80204200591550000302580108100800081008002050064013212002020039200399977699908012020080032200800322003920039118020110099100100800001000000111511801600200360800001002004020040200402004020040
80204200391550000722580108100800881008002050064013212002020039200399977699908012020080032200800322003920039118020110099100100800001000100111511801600200360800001002004020040200402004020040
80204200391550000302580108100800081008002050064013212002020039200399977699908012020080032200800322003920039118020110099100100800001000000111511801600200365800001002004020040200402004020040
80204200391600000302580108100800081008002050064013202002020039200399977699908012020080032200800322003920039118020110099100100800001000003111511801600200360800001002004020040200402004020040
80204200391550090302580108100800081008002050064013202002020039200399977699908012020080032200800322003920039118020110099100100800001000000111511801600200360800001002004020040200402004020040
80204200391550000302580108100800081008002050064013202002020039200399977699908012020080032200800322003920039118020110099100100800001000003111511801600200360800001002004020040200402004020040
80204200391560000302580108100800081008002050064013202002020039200399977699908012020080032200800322003920039118020110099100100800001000000111511811601200360800001002004020040200402004020040
80204200391550000302580108100800081008002050064013212002020039200399977699908012020080032200800322003920039118020110099100100800001000000111511801600200360800001002004020040200402004020040
80204200391560000302580108100800081008002050064013202002020039200399977699908012020080032200800322003920039118020110099100100800001000000111511801600200360800001002004020040200402004020040
802042003915500001892580108100800081008002050064013202002020039200399977699908012020080032200800322003920039118020110099100100800001000000111511801600200360800001002004020040200402004020040

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)5f60696d6edispatch 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)9faccfd0d5d6daddinst fetch restart (de)dfe0? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
8002420050150040258001010800001080000506400000120020200392003999963100198001020800002080000200392003911800211091010800001005024371604432003680000102004020040200402004020040
8002420039150040258001010800001080000506400000120020200392003999963100198001020800002080000200392003911800211091010800001005024351603332003680000102004020040200402004020040
8002420039150040258001010800001080000506400000120020200392003999963100198001020800002080000200392003911800211091010800001005024331602232003680000102004020040200402004020040
80024200391500402580010108000010800005064000001200202003920039100113100198001020800002080000200392003911800211091010800001005024331604432003680000102009620040200402004020040
8002420039150040258001010800001080000506400000020020200392003999963100198001020800002080000200392003911800211091010800001005024331602232003680000102004020040200402004020040
80024200391500402580010108000010800005064000001200202003920039999631001980010208000020800002003920039118002110910108000010050242431603232003680000102004020040200402004020040
800242003915001492580010108000010800005064000000200202003920039999631001980010208000020800002003920039118002110910108000010050242431604232003680000102004020040200402004020040
80024200391500402580010108000010800005064000000200202003920039999631001980010208000020800002003920039118002110910108000010050242441602232003680000102004020040200402004020040
80024200391500402580010108000010800005064000000200202003920039999631001980010208000020800002003920039118002110910108000010050242431603332003680000102004020040200402004020040
80024200391500402580010108000010800005064000000200202003920039999631001980010208000020800002003920039118002110910108000010050242451602332003680000102004020040200402004020040