Apple M1 Microarchitecture Research by Dougall Johnson

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

FCVTMU (vector, 8H)

Test 1: uops

Code:

  fcvtmu v0.8h, v0.8h
  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)03181e1f3f4e51inst 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)a8acc2cfd5d6ddinst fetch restart (de)e0? fp/simd (ee)f5f6f7f8fd
100430372300061254725100010001000398160030183037303724143289510001000100030373037111001100026073116112629100030383038303830383038
100430372400061254725100010001000398160030183037303724143289510001000100030373037111001100000073116112629100030383038303830383038
100430372400061254725100010001000398160030183037303724143289510001000100030373037111001100000073116112629100030383038303830383038
100430372400061254725100010001000398160030183037303724143289510001000100030373037111001100000073116112629100030383038303830383038
100430372300061254725100010001000398160030183037303724143290710001000100030373037111001100000473116112629100030383038303830383038
10043037240088103254725100010001000398160030183037303724143289510001000100030373037111001100000273116112629100030383038303830383038
100430372300061254725100010001000398160030183037303724143289510001000100030373037111001100000073116112629100030383038303830383038
1004307024012061254725100010001000398160030183037303724143289510001000100030373037111001100000073116112629100030383038303830383038
1004303723012082254725100010001000398160030183037303724143289510001000100030373037111001100000073116112629100030383038303830383038
100430372400061254725100010001000398160030183037303724143289510001000100030373037111001100000073116112629100030383038303830383038

Test 2: Latency 1->2

Code:

  fcvtmu v0.8h, v0.8h
  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)03071e3a3f4e51inst 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)60696b6d6edispatch 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? int output thing (e9)? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
102043003723310021582954725101001001000010010000500427716013001803003730037282643287451010020010000200100003003730037111020110099100100100001000071011611296330100001003003830038300383003830038
102043003723201204202954725101001251000010010000626427716013001803003730037282643287451010020010000200100003003730037111020110099100100100001000071011611296330100001003003830038300383003830038
10204300372330008322954725101001001000010010000500427716013001803003730037282643287451010020010000200100003003730037111020110099100100100001000071011622296330100001003003830038300383003830038
10204300372330003592954725101001001000010010000500427716013001803003730037282643287451010020010000200100003003730037111020110099100100100001000071211611296330100001003003830038300383003830038
10204300372330003802954725101001001000010010000500427716013001803003730037282643287451010020010000200100003003730037111020110099100100100001000071011611296330100001003003830038300383003830038
10204300372330009312954725101001001000010010000500427716013001803003730037282643287451010020010000200100003003730037111020110099100100100001000071011611296330100001003003830038300383003830038
10204300372330009432954725101251251000012510000500427716013001803003730037282643287451010020010000200100003003730037111020110099100100100001000071011611296330100001003003830038300383003830038
102043003723300088229547251010010010000100100005004277160130018030037300372826432874510100200100002001000030037300371110201100991001001000010000710116112963325100001003003830038300383003830038
10204300372330003152954725101001001000010010000500427716013001833003730037282643287451010020010000200100003003730037111020110099100100100001000071011611296330100001003003830038300383003830038
10204300372330004822954725101001001000010010000500427716013001803003730037282643287451010020010000200100003003730037111020110099100100100001000071011611296330100001003003830038300383003830038

1000 unrolls and 10 iterations

Result (median cycles for code): 3.0037

retire (01)cycle (02)03080b18191e1f3f4e51inst 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)9fa1a6a8acc2cfd5d6ddinst fetch restart (de)e0? int output thing (e9)? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
10024300372330000006129547251001010100001010000504277160030018300373003728286328767100102010000201000030084300371110021109101010000100048306402162229629010000103003830038300383003830038
1002430037233000000612954725100101010000101000050427716003001830037300372828632876710010201000020100003003730037111002110910101000010000906402162229629010000103003830038300383003830038
1002430037233000000717295472510010101000010100005042771600300183003730037282863287671001020100002010000300373003711100211091010100001000015906402162229629010000103003830038300383003830038
100243003722500001206129529631002814100161110150554279864030090301323013228290122880410313201032520102473013130085211002110910101000010220346639334329701210000103008530084300853008630086
10024300842251112480176126329547251001010100001010000504277160030018300373003728286328767100102010000201000030037300371110021109101010000100009926402162229629010000103013330038300383003830038
1002430037225000000612954725100191010000101000050427716003001830037300372828632876710010201016220100003003730037211002110910101000010000326612244429737010000103003830038300383003830038
100243003722500001506129547251001010100001010000504277160130018300373003728286328767100102010000201000030037300371110021109101010000100032406402162229629010000103003830038300383003830038
1002430037225000000612954725100621410024101000050427716003001830037300372828632876710010201000020100003003730037111002110910101000010008906402162229629010000103003830038300383003830038
1002430037225000000612954725100101010000101000050427716003001830037300372828632876710010201000020100003003730070111002110910101000010008606402162229629010000103003830038300383003830038
1002430037225000000612954725100101010000101000050427716003001830037300372828632876710010201000020100003003730037111002110910101000010003006402162229629010000103003830038300383003830038

Test 3: throughput

Count: 8

Code:

  fcvtmu v0.8h, v8.8h
  fcvtmu v1.8h, v8.8h
  fcvtmu v2.8h, v8.8h
  fcvtmu v3.8h, v8.8h
  fcvtmu v4.8h, v8.8h
  fcvtmu v5.8h, v8.8h
  fcvtmu v6.8h, v8.8h
  fcvtmu v7.8h, v8.8h
  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)0304080a0b18191e1f3a3f51inst 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)9fa0a1a6a8a9acc5branch mispredict (cb)cdcfd5d6ddinst fetch restart (de)e0? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
80204200391550000000029125801081008000810080020500640132020020200392003999776999080120200800322008003220039200391180201100991001008000010000000311151228168820036800001002004020040200402004020040
80204200391550000000023525801081008000810080020500640132020020200392003999776999080120200800322008003220039200391180201100991001008000010000000011151228168820036800001002004020040200402004020040
80204200391550000000023525801081008000810080020500640132020020200392003999776999080120200800322008003220039200391180201100991001008000010000000011151228168820036800001002004020040200402004020040
80204200391560000000027725801081008000810080020500640132120020200392003999776999080120200800322008003220039200391180201100991001008000010000000011151228166620036800001002004020040200402004020040
802042003915500000000251025801081008000810080020500640132020020200392003999776999080120200800322008003220039200391180201100991001008000010000000011151208168820036800001002004020040200402004020040
80204200391550000000023525801081008000810080020500640132120020200392003999776999080120200800322008003220039200391180201100991001008000010000010011151228169820036800001002004020040200402004020040
80204200391550000000023525801081008000810080020500640132120020200392003999776999080120200800322008003220039200391180201100991001008000010000000011151228168820036800001002004020040200402004020040
802042003915500000012023525801081008000810080020500640132120020200392003999776999080120200800322008003220039200391180201100991001008000010000010011151228168820036800001002004020040200402004020040
80204200391560000000023525801081008000810080020500640132120020200392003999776999080120200800322008003220039200391180201100991001008000010000010011151228166820036800001002004020040200402004020040
80204200391550000000023525801081008000810080020500640132020020200392003999776999080120200800322008003220039200391180201100991001008000010000000011151228163820036800001002004020040200402004020040

1000 unrolls and 10 iterations

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

retire (01)cycle (02)031e1f3f51inst 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)9fa8acc2cfd5d6ddinst fetch restart (de)e0? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
800242003915500402580010108000010800005064000002002020039200399996310019800102080000208000020039200391180021109101080000100005020750752003680000102004020040200402004020040
8002420039161002052580010108000010800005064000002002020039200399996310019800102080000208000020039200391180021109101080000101005020316552003680000102004020040200402004020040
800242003915600402580010108000010800005064000002002020039200399996310019800102080105208009820039200391180021109101080000100005020316542003680000102004020040200402004020040
8002420039155004025800101080000108000050640000020020200392003910011310019800102080000208000020039200391180021109101080000100005020516532003680000102004020040200402004020040
80024200391561202072580010108000010800005064000002002020039200399996310019800102080000208000020039200391180021109101080000101005020516562003680000102004020040200402004020040
8002420039156002092580010108000010800005064000002002020039200399996310019800102080000208000020039200391180021109101080000100005020416352003680000102004020040200402004020040
800242003915500632580010108000010800005064000002002020039200399996310019800102080000208000020039200391180021109101080000100005020316642003680000102004020040200402004020040
8002420039155003392580010108000010800005064000002002020039200399996310019800102080000208000020039200391180021109101080000100005020616462003680000102004020040200402004020040
800242003915500402580010108000010800005064000002002020039200399996310019800102080000208000020039200391180021109101080000100005020516552003680000102004020040200402004020040
800242003915500612580010108000010800005064000002002020039200399996310019800102080000208000020039200391180021109101080000100005020516532003680000102004020040200402004020040