Apple M1 Microarchitecture Research by Dougall Johnson

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

FCVTNU (scalar, D to D)

Test 1: uops

Code:

  fcvtnu d0, d0
  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
100430372406125472510001000100039816013018303730372414328951000100010003037303711100110000073116112629100030383038303830383038
100430372496125472510001000100039816003018303730372414328951000100010003037303711100110003373116112629100030383038303830383038
100430372306125472510001000100039816003018303730372414328951000100010003037303711100110000073116112629100030383038303830383038
100430372406125472510001000115039816013018303730372414328951000100010003037303711100110000073116112629100030383038303830383038
100430372306125472510001000100039816003018303730372414328951000100010003037303711100110000673116112629100030383038303830383038
100430372306125472510001000100039816003018303730372414328951000100010003037303711100110000973116112629100030383038303830383038
100430372406125472510001000100039816003018303730372414328951000100010003037303711100110000973116112629100030383038303830383038
100430372306125472510001000100039816003018303730372414328951000100010003037303711100110000073116112629100030383038303830383038
100430372408225472510001000100039816003018303730372414328951000100010003037303711100110000373116112629100030383038303830383038
100430372406125472510001000100039816003018303730372414328951000100010003037303711100110000073116112629100030383038303830383038

Test 2: Latency 1->2

Code:

  fcvtnu d0, d0
  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)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)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)9fa0a1a6a8accfd5d6ddinst fetch restart (de)e0? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
1020430037233019129547251010010010000100100005004277160130018300373003728264328745101002001000020010000300373003711102011009910010010000100420007101161129633100001003003830038300383003830038
1020430037232014529547251010010010000100100005004277160030018300373003728264328745101002001000020010000300373003711102011009910010010000100000007101161129633100001003003830038300383003830038
102043003723327454429547251010010010000100100005004277160030018300373003728264328745101002001000020010000300373003711102011009910010010000100000007101161129633100001003003830038300383003830038
102043003723306129547251010010010000100100005004277160130018300373003728264328745101002001000020010000300373003711102011009910010010000100000007101161129633100001003003830038300383003830038
1020430037233032429547251010010010000100100005004277160130018300373003728264328745101002001000020010000300373003711102011009910010010000100000107101161129633100001003003830038300383003830038
10204300372330295829547251010010010000100100005004277160130018300373003728264328745101002001000020010000300373003711102011009910010010000100000007101161129633100001003003830038300383003830038
102043003723306129547251010010010000100100005004277160030018300373003728264328745101002001000020010000300373003711102011009910010010000100002307101161129633100001003003830038300383003830038
102043003723306129547251010010010000100100005004277160030018300373003728264328745101002001000020010000300373003711102011009910010010000100000007101161129633100001003003830038300383003830038
102043003723306129547251010010010000100100005004277160030018300373003728264328745101002001000020010000300373003711102011009910010010000100000007101161129633100001003003830038300383003830038
1020430037233012429547251010010010000100100005004277160130018300373003728264328745101002001000020010000300373003711102011009910010010000100000007101161129633100001003003830038300383003830038

1000 unrolls and 10 iterations

Result (median cycles for code): 3.0037

retire (01)cycle (02)030b1e3f4e51inst 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)9fa8acbranch mispredict (cb)cfd5d6daddinst fetch restart (de)e0? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
10024300372330336129547251001010100001010000504277160130018300373003728286328767100102010000201000030037300371110021109101010000100006402160222962910000103003830038300383003830038
1002430037233006129547251001010100001010000504277160030018300373003728286328767100102010000201000030037300371110021109101010000100006402160222962910000103003830038300383003830038
1002430037233006129547251001010100001010000504277160030018300373003728286328767100102010000201000030037300371110021109101010000100006402160222962910000103003830038300383003830038
1002430037233006129547251001010100001010000504277160130018300373003728286328767100102010000201000030037300371110021109101010000100006402160222962910000103003830038300383003830038
1002430037233006129547251001010100001010000504277160030018300373003728286328767101602010000201000030037300371110021109101010000100006402160222970110000103003830038300383003830038
1002430037233006129547251001010100001010000504277160030018300373003728286328767100102010000201000030037300371110021109101010000100006402160222962910000103003830038300383003830038
10024300372320072629547251001010100001010000504277160030018300373003728286328767100102010000201000030037300371110021109101010000100006402160222962910000103003830038300383003830038
1002430037233006129547251001010100001010000504277160030018300373003728286328767100102010000201000030037300371110021109101010000100006402160222962910000103003830038300383003830038
100243003722500171429547251001010100001010000504277160030018300373003728286328767100102010000201000030037300371110021109101010000100006402160222962910000103003830038300383003830038
1002430037225006129547251001010100001010000504277160030018300373003728286328767100102010000201000030037300371110021109101010000100006402160222962910000103003830038300383003830038

Test 3: throughput

Count: 8

Code:

  fcvtnu d0, d8
  fcvtnu d1, d8
  fcvtnu d2, d8
  fcvtnu d3, d8
  fcvtnu d4, d8
  fcvtnu d5, d8
  fcvtnu d6, d8
  fcvtnu d7, d8
  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)03071e1f3f51inst 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)9fa1a8a9acc5c8branch mispredict (cb)cdcfd5d6ddinst fetch restart (de)e0? int output thing (e9)? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
8020420039155145030258010810080008100800205006401321201892003920039997706999080120200800322008003220039200391180201100991001008000010000001011511801600200360800001002004020040200402004020040
802042003915600030268011610080016100800285006401961200292004820048997609998680128200800382008003820048200481180201100991001008000010000002022512912311200450800001002004920049200492004920049
802042025615500064278011610080016100800285006401961200292004820049997609998680128200800382008003820048200481180201100991001008000010000002022512812311200450800001002004920049200502005020049
802042004815500064268011610080016100800285006401961200292004820049997609998680128200800382008003820048200481180201100991001008000010000002022512912311200460800001002004920049200502004920050
8020420049155000642780116100800161008002850064019612002920048200489976010998680128200800382008003820048200481180201100991001008000010000002022512812311200460800001002004920049200492004920050
802042004815600030258010810080008100800205006401321200202003920039997706999080120200800322008003220039200391180201100991001008000010000001011511801600200360800001002004020040200402004020040
802042003916103094258010810080008100800205006401321200202003920039997706999080120200800322008003220039200391180201100991001008000010000001011511811600200360800001002004020040200402004020040
802042003915600030258010810080008100800205006401321200722003920039997706999080120200800322008045220039200391180201100991001008000010000001011511801600200360800001002004020040200402004020040
802042003915500030258010810080008100800205006401321200202003920039997706999080120200800322008003220039200391180201100991001008000010003001011511801600200361800001002004020040200402004020040
8020420039155000302580108100800081008002050064013212002020039200399977014999080120200800322008003220039200391180201100991001008000010000001011511801600200360800001002004020040200402004020040

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)5f60696b6d6edispatch 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)9fa8accfd5d6ddinst fetch restart (de)e0? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
800242003915504025800101080000108000050640000002002002003920039999631001980010208000020800002003920039118002110910108000010005020516442003680000102004020040200402004020040
800242003915504025800101080000108000050640000002002002003920039999631001980010208000020800002003920039118002110910108000010005020316342003680000102004020040200402004020040
800242003915504025800101080000108000050640000002002002003920039999631001980010208000020800002003920039118002110910108000010005020616872003680000102004020040200402004020040
800242003915594025800101080000108000050640000002002002003920039999631001980010208000020800002003920039118002110910108000010005020616772003680000102004020040200402004020040
800242003915604025800101080000108000050640000002002002003920039999631001980010208000020800002003920039118002110910108000010005020316772003680000102004020040200402004020040
800242003915504025800101080000108000050640000002002002003920039999631001980010208000020800002003920039118002110910108000010035020416742003680000102004020040200402004020040
800242003915504025800101080000108000050640000002002002003920039999631001980010208000020800002003920039118002110910108000010005020716342003680000102004020040200402004020040
8002420039155070525800101080000108000050640000002002002003920039999631001980010208000020800002003920039118002110910108000010005020416762003680000102004020040200402004020040
800242003915504025800101080000108000050640000002002002003920039999631001980010208000020800002003920039118002110910108000010005020616342003680000102004020040200402004020040
8002420039155042825800101080000108000050640000002002002003920039999631001980010208000020800002003920039118002110910108000010005020416742003680000102004020040200402004020040