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, H to H)

Test 1: uops

Code:

  fcvtnu h0, h0
  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)03080a191e3f4e51inst 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)a8a9acc2cfd5d6ddinst fetch restart (de)e0? fp/simd (ee)f5f6f7f8fd
100430372300007312547251000100010003981600301830373037241432895100010001000303730371110011000000073216222629100030383038303830383038
10043037240000612547251000100010003981601301830373037241432895100010001000303730371110011000000173216222629100030383038303830383038
10043037230000612547251000100010003981601301830373037241432895100010001000303730371110011000000073216222629100030383038303830383038
10043037240000892547251000100010003981600301830373037241432895100010001000303730371110011000003073216222629100030383038303830383038
10043037240100612547251000100010003981600301830373037241432895100010001000303730371110011000000073216222629100030383038303830383038
10043037230000612547251000100010003981600301830373037241432895100010001000303730371110011000003073216222629100030383038303830383038
100430372300001032547251000100010003981601301830373037241432895100010001000303730371110011000000073216222629100030383038303830383038
100430372300001032547251000100010003981601301830373037241432895100010001000303730371110011000000073216222629100030383038303830383038
100430372300001032547251000100010003981601301830373037241432895100010001000303730371110011000103073216222629100030383038303830383038
10043037240000612547251000100010003981600301830373037241432895100010001000303730371110011000000073216222629100030383038303830383038

Test 2: Latency 1->2

Code:

  fcvtnu h0, h0
  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)031e3f4e5051inst 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)9fa8a9acc2c5cfd5d6ddinst fetch restart (de)e0? int output thing (e9)? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
10204300372320842954702510100100100001041000050042785121300183003730084282647287801010020010064208100003003730037311020110099100100100001000000071011611296330100001003003830038300383003830038
102043003723301032954702510100100100001001000050042771601300183003730037282643287451010020010000200100003003730037111020110099100100100001000000071011611296330100001003003830038300383003830038
102043003723303442954702510100100100001001000050042771601300183003730037282643287451010020010000200100003003730037111020110099100100100001000000071011611296330100001003003830038300383003830038
102043003723304652954706310100100100001001000050042771601300183008530037282643287451010020610000200100003003730037111020110099100100100001000000071011611296330100001003003830038300383003830038
102043003723301032954702510100100100001001000050042771600300183003730037282643287451010020010000200100003003730037111020110099100100100001000000074111611296330100001003003830038300383003830038
10204300372330612954702510100100100001001000050042771601300183003730037282643287451010020010000200100003003730037111020110099100100100001000000071011611296330100001003003830038300383003830038
10204300372330612954702510100100100001001000050042771601300183003730037282643287451010020010000200100003003730037111020110099100100100001001030071011611296330100001003003830038300383003830038
1020430037232125072954702510100100100001001000050042771601300183003730037282643287451010020010000200100003003730037111020110099100100100001000000071011611296330100001003003830038300383003830038
10204300372320842954702510100100100001001000050042771601300183003730037282643287451010020010000200100003003730037111020110099100100100001000000071011611296330100001003003830038300383003830038
102043003724101922954702510100100100001001000050042771601300183003730037282643287451010020010000200100003003730037111020110099100100100001000002071011611296330100001003003830038300383003830038

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)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)9fa8c5cfd5d6ddinst fetch restart (de)e0? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
1002430037224061295472510010101000010100005042771600300183003730037282863287671001020100002010000300373003711100211091010100001000640216222962910000103003830038300383003830038
10024300372250451295472510010101000010100005042771600300183003730037282863287671001020100002010000300373003711100211091010100001000640216222962910000103003830038300383003830038
10024300372250105295472510010101000010100005042771600300183003730037282863287671001020100002010000300373003711100211091010100001000640216222962910000103003830038300383003830038
10024300372250151295472510010101000010100005042771600300183003730037282863287671001020100002010000300373003711100211091010100001000640216232962910000103003830038300383003830038
10024300372250481295472510010101000010100005042771601300183003730037282863287671001020100002010000300373003711100211091010100001000640216222962910000103003830038300383003830038
10024300372250145295472510010101000010100005042771600300183003730037282863287671001020100002010000300373003711100211091010100001000640216222962910000103003830038300383003830038
10024300372250147295472510010101000010100005042771601300183003730037282863287671001020100002010000300373003711100211091010100001000640216222962910000103003830038300383003830038
10024300372250105295472510010101000010100005042771600300183003730037282863287671001020100002010000300373003711100211091010100001000640216222962910000103003830038300383003830038
10024300372250105295472510010101000010100005042771601300183003730037282863287671001020100002010000300373003711100211091010100001000640216222962910000103003830038300383003830038
10024300372240170295472510010101000010100005042771600300183003730037282863287671001020100002010000300373003711100211091010100001000640216222962910000103003830038300383003830038

Test 3: throughput

Count: 8

Code:

  fcvtnu h0, h8
  fcvtnu h1, h8
  fcvtnu h2, h8
  fcvtnu h3, h8
  fcvtnu h4, h8
  fcvtnu h5, h8
  fcvtnu h6, h8
  fcvtnu h7, h8
  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)03070a0b18191e1f3a3f51inst 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)9fa1a7a8acc5branch mispredict (cb)cdcfd5d6ddinst fetch restart (de)e0? int output thing (e9)? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
8020420058155000000001112580108100800081008002050064013202002020039200399977699908012020080032200800322003920039118020110099100100800001000003111511801610200360800001002004020040200402004020040
802042003915500000000512580108100800081008002050064013202002020039200399977699908012020080032200800322003920039118020110099100100800001000000111511801600200360800001002004020040200402004020040
802042003915500000000302580108100800081008002050064013202002020039200399977699908012020080032200800322003920039118020110099100100800001000000111511801600200360800001002004020040200402004020040
80204200391550000069003025801081008000810080020500640132020020200392003999776999080120200800322008003220039200391180201100991001008000010000021111511801600200360800001002004020040200402004020040
802042003915500000000302580108100800081008002050064013202002020039200399977699908012020080032200800322003920039118020110099100100800001000000111511801600200360800001002004020040200402004020040
802042003915600000000302580108100800081008002050064013202002020039200399977699908012020080032200800322003920039118020110099100100800001000000111511801600200360800001002004020040200402004020040
802042003916100000000302580108100800081008002050064013202002020039200399977699908012020080032200800322003920039118020110099100100800001000000111511801600200360800001002004020040200402004020040
802042003915600000000302580108100800081008002050064013202002020039200399977699908012020080032200800322003920039118020110099100100800001000000111511801600200360800001002004020040200402004020040
8020420039155000001200302580108100800081008002050064013202002020039200399977699908012020080032200800322003920039118020110099100100800001000000111511801600200360800001002004020040200402004020040
802042003915600000000302580108100800081008002050064013202002020039200399977699908012020080032200800322003920039118020110099100100800001000000111511801600200360800001002004020040200402004020040

1000 unrolls and 10 iterations

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

retire (01)cycle (02)0318191e3f51inst 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)9fa1a6a8a9accdcfd0d2d5d6dadbddinst fetch restart (de)e0? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
800242005015500082258001010800001080000506400000020020200392003999963100198001020800002080000200392003911800211091010800001000000050200021600112003680000102004020040200402004020040
800242003915600040258001010800001080000506400000020020200392003999963100198001020800002080000200392003911800211091010800001000000050200011600112003680000102004020040200402004020040
800242003915500082258001010800001080000506400000020020200392003999963100198001020800002080000200392003911800211091010800001000000050200011600112003680000102004020040200402004020040
8002420039156000515258001010800001080000506400000020020200392003999963100198001020800002080000200392003911800211091010800001000000150200111600112003680000102004020040200402004020040
800242003915500040258001010800001080000506400000020020200392003999963100198001020800002080000200392003911800211091010800001000000050200011600112003680000102004020040200402004020040
800242003915500040258001010800001080000506400000120020200392003999963100198001020800002080000200392003911800211091010800001000000050200021600112003680000102004020040200402004020040
800242003915500082258001010800001080000506400000020020200392003999963100198001020800002080000200392003911800211091010800001000000050203011600122003680000102004020040200402004020040
800242003915600040258001010800001080000506400000020020200392003999963100198001020800002080000200392003911800211091010800001000000050200011600112003680000102004020040200402004020040
8002420039156000515258001010800001080000506400000020020200392003999963100198001020800002080000200392003911800211091010800001000000050200011600112003680000102004020040200402004020040
800242003915500040258001010800001080000506400000120020200392003999963100198001020800002080000200392003911800211091010800001000000050200021600112003680000102004020040200402004020040