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, integer, H to H)

Test 1: uops

Code:

  fcvtzu 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)03080b18191e1f3f4e51inst 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)a0a1a6a7a8a9acc2cfd5d6ddinst fetch restart (de)e0? fp/simd (ee)f5f6f7f8fd
1004303724000039010325472510001000100039816013018303730372414328951000100010003037303711100110000000000073116112629100030383038303830383038
10043037240000006125472510001000100039816013018303730372414328951000100010003037303711100110000000100073116112629100030383038303830383038
100430372300005707525472510001000100039816013018303730372414328951000100010003037303711100110000000000073116112629100030383038303830383038
10043037240000306125472510001000100039816003018303730372414328951000100010003037303711100110000000000073116112629100030383038303830383038
10043037240000006125472510001000100039816003018303730372414328951000100010003037303711100110000000000073116112629100030383038303830383038
10043037230000006125472510001000100039816003018303730372414328951000100010003037303711100110000000000073116112629100030383038303830383038
10043037230000006125472510001000100039816003018303730372414328951000100010003037303711100110000000003073116112629100030383038303830383038
100430372400001206125472510001000100039816003018303730372414328951000100010003037303711100110000000000073116112629100030383038303830383038
10043037240000006125472510001000100039816003018303730372414328951000100010003037303711100110000000003073116112629100030383038303830383038
1004303724000015906125472510001000100039816003018303730372414328951000100010003037303711100110000000000073116112629100030383038303830383038

Test 2: Latency 1->2

Code:

  fcvtzu 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)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)9fa8accdcfd5d6ddinst fetch restart (de)e0? int output thing (e9)eb? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
1020430037233010329547251010010010000100100005004277160130018300373003728264328745101002001000020010000300373003711102011009910010010000100200710116112963300100001003003830038300383003830038
102043003723206129547251010010010000100100005004277160130018300373003728264328745101002001000020010000300373003711102011009910010010000100230710116112963300100001003003830038300383003830038
1020430037233061295472510100100100001001000050042771601300183003730037282643287451010020010000200100003003730037111020110099100100100001000751710116112963300100001003003830038300383003830038
1020430037232216129547251010010010000100100005004277160130018300373003728264328745101002001000020010000300373003711102011009910010010000100100710116112963300100001003003830038300383003830038
102043003723306129547251010010010000100100005004277160030018300373003728264328745101002001000020010000300373003711102011009910010010000100500710116112963300100001003003830038300383003830038
102043003723306129547251010010010000100100005004277160030018300373003728264328745101002001000020010000300373003711102011009910010010000100200710116112963300100001003003830038300383003830038
1020430037233061295472510100100100001001000050042771601300183003730037282643287451010020010000200100003003730037111020110099100100100001002000710116112963300100001003003830038300383003830038
1020430037233072629547251010010010000100100005004277160030018300373003728264328745101002001000020010000300373003711102011009910010010000100200710116112963300100001003003830038300383003830038
102043003723306129547251010010010000100100005004277160130018300373003728264328745101002001000020010000300373003711102011009910010010000100200710116112963300100001003003830038300383003830038
102043003723206129547251010010010000100100005004277160130018300373003728264328745101002001000020210000300373003711102011009910010010000100100710116112963300100001003003830038300383003830038

1000 unrolls and 10 iterations

Result (median cycles for code): 3.0037

retire (01)cycle (02)030918191e1f3f4e51inst 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)9fa1a8a9accfd5d6ddinst fetch restart (de)e0? int output thing (e9)ea? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
10024300372250000061295472510010101000010100005042771601300183003730037282860328767100102010000201000030037300371110021109101010000100320064021622296290010000103003830038300383003830038
10024300372250000015629547251001010100001010000504277160130018300373003728286032876710010201000020100003003730037111002110910101000010090964021622296290010000103003830038300383003830038
100243003722500000726295472510010101000010100005042771601300183003730037282860328767100102010000201000030037300371110021109101010000100220364021622296290010000103003830038300383003830038
10024302252240000061295472510010101000010100005042771600300543003730037282860328767100102010000201000030037300371110021109101010000100109664021622296290010000103003830038300383003830038
1002430037234000006129547251001010100001010000504277160130018300373003728286032876710010201000020100003003730037111002110910101000010030064021622296290010000103003830038300383003830038
10024300372250000061295472510010101000010100005042771600300183003730037282860328767100102010000201000030037300371110021109101010000100006964021622296290010000103003830038300383003830038
100243003722500000612954725100211010000101015071427716013005430037300372828603287671001020100002010000300373003711100211091010100001022021264021622296290010000103003830038300383003830038
10024300372250000010329547251001010100001010000504277160130018300373003728286032876710010201000020100003003730037111002110910101000010040964021622296290010000103003830038300383003830038
1002430037225000120103295472510010101000010100005042771601300183003730037282860328767100102010000201000030037300371110021109101010000100008764021622296290010000103003830038300383003830038
10024300372240000061295472510010101000010100005042771601300183003730037282860328767100102010000201000030037300371110021109101010000100008464021622296290010000103003830038300383003830038

Test 3: throughput

Count: 8

Code:

  fcvtzu h0, h8
  fcvtzu h1, h8
  fcvtzu h2, h8
  fcvtzu h3, h8
  fcvtzu h4, h8
  fcvtzu h5, h8
  fcvtzu h6, h8
  fcvtzu 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)03181e3f51inst 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)9fa3a8acc5branch mispredict (cb)cdcfd0d5d6ddinst fetch restart (de)e0? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
802042003915600125258010810080008100800205006401320200202003920039997769990801202008003220080032200392003911802011009910010080000100000111511800160020036800001002004020141200402004020040
80204200391560030258010810080008100800205006401320200202003920039997769990801202008003220080032200392003911802011009910010080000100000111511800160020036800001002004020040200402004020040
8020420039155001292258010810080008100800205006401320200202003920039997769990801202008003220080032200392003911802011009910010080000100000111511800160020036800001002004020040200402004020040
80204200391550030258010810080008100800205006401320200202003920039997769990801202008003220080032200392003911802011009910010080000100000111511800160020036800001002004020040200402004020040
80204200391560072258010810680008100800205006401320200202003920039997769990801202008003220080032200392003911802011009910010080000100003111511800160020036800001002004020040200402004020040
80204200391550030258010810080008100800205006401320200202003920039997769990801202008003220080032200392003911802011009910010080000100000111511800160020036800001002004020040200402004020040
80204200391550030258010810080008100800205006401320200202003920039997769990801202008003220080032200392003911802011009910010080000100000111511800160020036800001002004020040200402004020040
80204200391560030258010810080008100800205006401320200202003920039997769990801202008003220080032200392003911802011009910010080000100000111511800160020036800001002004020040200402004020040
80204200391550030258010810080008100800205006401320200202003920039997769990801202008003220080032200392003911802011009910010080000100013111511800160020036800001002004020040200402004020040
80204200391550030258010810080008100800205006401320200202003920039997769990801202008003220080032200392003911802011009910010080000100000111511800160020036800001002004020040200402004020040

1000 unrolls and 10 iterations

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

retire (01)cycle (02)031e3a3f51inst 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)9fa8acc5cfd0d5d6ddinst fetch restart (de)e0? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
80024200391550040258001010800001080000506400000120020200392003999963100198001020800002080000200392003911800211091010800001000050200141612132003680000102004020040200402004020040
8002420039155120822580010108000010800005064000001200202003920039999631001980010208000020800002003920039118002110910108000010000502008168122003680000102004020040200402004020040
8002420039155004025800101080000108000050640000012002020039200399996310019800102080000208000020039200391180021109101080000100305020011167102003680000102004020040200402004020040
80024200391550040258001010800001080000506400000120020200392003999963100198001020800002080000200392003911800211091010800001000050200111611132003680000102004020040200402004020040
80024200391560082258001010800001080000506400000120020200392003999963100198001020800002080000200392003911800211091010800001020050200111613112003680000102004020040200402004020040
80024200391550082258001010800001080000506400000120020200392003999963100198001020800002280099200392011411800211091010800001010050200141613122003680000102004020040200402004020040
8002420039155004025800101080000108000050640000112002020039200399996310019800102080000208000020039200391180021109101080000100005020013167122003680000102004020040200402004020040
8002420039156004025800101080000108000050640000012002020039200399996310019800102080000208000020039200391180021109101080000101305020011161272003680000102004020040200402004020040
800242003915500515258001010800001080000506400000120020200392003999963100198001020800002080000200392003911800211091010800001000050200131612122003680000102004020040200402004020040
8002420039155004025800101080000108000050640000002002020039200399996310019800102080000208000020039200391180021109101080000100005020010161092003680000102004020040200402004020091