Apple Microarchitecture Research by Dougall Johnson

M1/A14 P-core (Firestorm): Overview | Base Instructions | SIMD and FP Instructions
M1/A14 E-core (Icestorm):  Overview | Base Instructions | SIMD and FP Instructions

FCVT (D to H)

Test 1: uops

Code:

  fcvt h0, 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 uop (01)cycle (02)03191e1f3f4e51schedule uop (52)schedule simd uop (54)dispatch simd uop (57)ldst uops in schedulers (5b)696d6emap stall dispatch (70)map rewind (75)map stall (76)dispatch uop (78)map simd uop (7e)map simd uop inputs (81)8283flush restart other nonspec (84)85inst all (8c)inst simd alu (9a)l1d cache writeback (a8)accfd5map dispatch bubble (d6)ddfetch restart (de)e0? simd retires (ee)f5f6f7f8fd
1004303722000612547251000100010003981603018303730372414328951000100010003037303711100110000073116112629100030383038303830383038
1004303723000612547251000100010003981603018303730372414328951000100010003037303711100110000073116112629100030383038303830383038
1004303722000612547251000100010003981603018303730372414328951000100010003037303711100110000073116112629100030383038303830383038
1004303723000612547251000100010003981603018303730372414328951000100010003037303711100110000073116112629100030383038303830383038
10043037230120612547251000100010003981603018303730372414328951000100010003037303711100110000073116112629100030383038303830383038
1004303722090612547251007100010003981603018303730372414328951000100010003037303711100110000073116112629100030383038303830383038
1004303723000612547251000100010003981603018303730372414328951000100010003037303711100110000073116112629100030383038303830383038
10043037230240612547251000100010003981603018303730372414328951000100010003037303711100110000073116112629100030383038303830383038
1004303722060612547251000100010003981603018303730372414328951000100010003037303711100110000073116112629100030383038303830383038
1004303723060612547251000100010003981603018303730372414328951000100010003037303711100110000073116112629100030383038303830383038

Test 2: Latency 1->2

Code:

  fcvt h0, 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 uop (01)cycle (02)031e1f3a3f4e51schedule uop (52)schedule int uop (53)schedule simd uop (54)dispatch int uop (56)dispatch simd uop (57)int uops in schedulers (59)ldst uops in schedulers (5b)60696d6emap stall dispatch (70)map rewind (75)map stall (76)dispatch uop (78)map int uop (7c)map simd uop (7e)map int uop inputs (7f)map simd uop inputs (81)8283flush restart other nonspec (84)85inst all (8c)inst branch (8d)inst branch taken (90)inst branch cond (94)inst int alu (97)inst simd alu (9a)9fl1d tlb access (a0)ld unit uop (a6)st unit uop (a7)l1d cache writeback (a8)a9accfd5map dispatch bubble (d6)ddfetch restart (de)e0? int output thing (e9)? simd retires (ee)? int retires (ef)f5f6f7f8fd
1020430037224000612954725101001001000010010000500427716003001830037300372826432874510100200100002001000030037300371110201100991001001000010000020371011611296330100001003003830038300383003830038
1020430037225000612954725101001001000010010000500427716003001830037300372826432874510100200100002001000030037300371110201100991001001000010000000371011611296330100001003003830038300383003830038
10204300372240006129547251010010010000100100005004277160030018300373003728264328745101002001000020010000300373003711102011009910010010000100000390371011611296330100001003003830038300383003830038
1020430037224000612954725101001001000010010000500427716003001830037300372826432874510100200100002001000030037300371110201100991001001000010000000071011621296330100001003003830038300383003830038
1020430037225000612954725101001001000010010000500427716003001830037300372826432874510100200100002001000030037300371110201100991001001000010000010371011611296330100001003003830038300383003830038
1020430037225000612954725101001001000010010000500427716003001830037300372826432874510100200100002001000030037300371110201100991001001000010000010371011611296330100001003003830038300383003830038
10204300372250006129547251010010010000100100005004277160030018300373003728264328745101002001000020010000300373003711102011009910010010000100000550971011611296330100001003003830038300383003830038
1020430037225000612954725101001001000010010000500427716003001830037300372826432874510100200100002001000030037300371110201100991001001000010000010371011610296330100001003003830038300383003830038
1020430037225000942954725101001001000010010000500427716003001830037300372826432874510100200100002001000030037300371110202100991001001000010000000371011611296330100001003003830038300383003830038
1020430037225000612954725101001001000010010000500427716003001830037300372826432874510100200100002001000030037300371110201100991001001000010000010371011611296330100001003003830038300383003830038

1000 unrolls and 10 iterations

Result (median cycles for code): 3.0037

retire uop (01)cycle (02)03091e3f4e51schedule uop (52)schedule int uop (53)schedule simd uop (54)dispatch int uop (56)dispatch simd uop (57)int uops in schedulers (59)ldst uops in schedulers (5b)60696d6emap stall dispatch (70)map rewind (75)map stall (76)dispatch uop (78)map int uop (7c)map simd uop (7e)map int uop inputs (7f)map simd uop inputs (81)8283flush restart other nonspec (84)85inst all (8c)inst branch (8d)inst branch taken (90)inst branch cond (94)inst int alu (97)inst simd alu (9a)9fl1d cache writeback (a8)acbranch cond mispred nonspec (c5)cfd5map dispatch bubble (d6)ddfetch restart (de)e0? simd retires (ee)? int retires (ef)f5f6f7f8fd
100243003722510612954725100101010000101000050427716013001830037300372828632876710010201000020100003003730037111002110910101000010000640216222962910000103003830038300383003830038
100243003722500612954725100101010000101000050427716013001830037300372828632876710010201000020100003003730037111002110910101000010100640216222962910000103003830038300383003830038
100243003722500612954725100101010000101000050427716013001830037300372828632876710010201000020100003003730037111002110910101000010000640216222962910000103003830038300383003830038
100243003722500612954725100101010000101000050427716003001830037300372828632876710010201000020100003003730037111002110910101000010000640216222962910000103003830038300383003830038
100243003722500612954798100101010000101000050427716013001830037300372828632876710010201000020100003003730037111002110910101000010400640216222962910000103003830038300383003830038
100243003722500612954725100101010000101000050427716013001830037300372828632876710010201000020100003003730037111002110910101000010000640216222962910000103003830038300383003830038
100243003722500612954725100101010000101000050427716003001830037300372828632876710010201000020100003003730037111002110910101000010000640216222968910000103003830038300383003830038
100243003722500612954725100101010000101000050427716003001830037300372828632876710010201000020100003003730037111002110910101000010300640216222962910000103003830038300383003830038
100243003722506612954725100101010000101000050427716003001830037300372828632876710010201000020100003003730037111002110910101000010000640216222962910000103003830038300383003830038
100243003722500612954725100101010000101000050427716003001830037300372828632876710010201000020100003003730037111002110910101000010000640216222962910000103003830038300383003830038

Test 3: throughput

Count: 8

Code:

  fcvt h0, d8
  fcvt h1, d8
  fcvt h2, d8
  fcvt h3, d8
  fcvt h4, d8
  fcvt h5, d8
  fcvt h6, d8
  fcvt h7, 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 uop (01)cycle (02)031e3f51schedule uop (52)schedule int uop (53)schedule simd uop (54)dispatch int uop (56)dispatch simd uop (57)int uops in schedulers (59)ldst uops in schedulers (5b)60696d6emap stall dispatch (70)map rewind (75)map stall (76)dispatch uop (78)map int uop (7c)map simd uop (7e)map int uop inputs (7f)map simd uop inputs (81)8283flush restart other nonspec (84)85inst all (8c)inst branch (8d)inst branch taken (90)inst branch cond (94)inst int alu (97)inst simd alu (9a)9fld unit uop (a6)l1d cache writeback (a8)acbranch cond mispred nonspec (c5)branch mispred nonspec (cb)cdcfd5map dispatch bubble (d6)ddfetch restart (de)e0? int output thing (e9)? simd retires (ee)? int retires (ef)f5f6f7f8fd
8020420058150030258010810080088100800205006401320200202003920039997769990801202008003220080032200392003911802011009910010080000100030111511811600200361800001002004020040200402004020040
8020420039150030258010810080008100800205006401321200202003920039997769990801202008003220080032200392003911802011009910010080000100100111511801600200360800001002004020040200402004020040
8020420039150030258010810080008100800205006401321200202003920039997769990801202008003220080032200392003911802011009910010080000100000111511801600200360800001002004020040200402004020040
8020420039150030258010810080008100800205006401321200202003920039997769990801202008003220080032200392003911802011009910010080000100000111511801600200360800001002004020040200402004020040
8020420039150030258010810080008100800205006401321200202003920039997769990801202008003220080032200392003911802011009910010080000100000111511801600200360800001002004020040200402004020040
8020420039150030258010810080008100800205006401321200202003920039997769990801202008003220080032200392003911802011009910010080000100000111511801600200360800001002004020040200402004020040
8020420039150030258010810080008100800205006401321200202003920039997769990801202008003220080032200392003911802011009910010080000100000111511801600200360800001002004020040200402004020040
8020420039150030258010810080008100800205006401321200202003920039997769990801202008003220080032200392003911802011009910010080000100000111511801600200360800001002004020040200402004020040
8020420039150040258010810080008100800205006401321200202003920039997769990801202008003220080032200392003911802011009910010080000100006111511801600200360800001002004020040200402004020040
8020420039150030258010810080008100800205006401321200202003920039997769990801202008003220080032200392003911802011009910010080000100000111511801600200360800001002004020040200402004020040

1000 unrolls and 10 iterations

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

retire uop (01)cycle (02)03l1i tlb fill (04)1e3f51schedule uop (52)schedule int uop (53)schedule simd uop (54)dispatch int uop (56)dispatch simd uop (57)int uops in schedulers (59)ldst uops in schedulers (5b)60696d6emap stall dispatch (70)simd prf full (72)map rewind (75)map stall (76)dispatch uop (78)map int uop (7c)map simd uop (7e)map int uop inputs (7f)map simd uop inputs (81)8283flush restart other nonspec (84)85inst all (8c)inst branch (8d)inst branch taken (90)inst branch cond (94)inst int alu (97)inst simd alu (9a)9fl1d tlb access (a0)l1d cache writeback (a8)accdcfd5map dispatch bubble (d6)dbddfetch restart (de)e0? simd retires (ee)? int retires (ef)f5f6f7f8fd
800242005015000402580010108000010800005064000012002020039200399996031001980010208000020800002003920039118002110910108000010000050202716025242003680000102004020040200402004020040
800242003915000402580010108000010800005064000012002020039200399996031001980010208000020800002003920039118002110910108000010000050202549025252003680000102004020040200402004020040
800242003915000402580010108000010800005064000012002020039200399996031001980010208000020800002003920039118002110910108000010000050201716021162003680000102004020040200402004020040
800242003915000402580010108000010800005064000012002020039200399996031001980010208000020800002003920039118002110910108000010000050202516014252003680000102004020040200402004020040
800242003915000402580010108000010800005064000012002020039200399996031001980010208000020800002003920039118002110910108000010000050202516028262003680000102004020040200402004020040
800242003915000402580010108000010800005064000012002020039200399996031001980010208000020800002003920039118002110910108000010000050201216025182003680000102004020040200402004020040
8002420039150004025800101080000108000050640000020020200392003999960310019800102080000208000020039200391180021109101080000100580050202716027142003680000102004020040200402004020040
800242003915000402580010108000010800005064000012002020039200399996031001980010208000020800002003920039118002110910108000010000050201616026152003680000102004020040200402004020040
800242003915000402580010108000010800005064000012002020039200399996031001980010208000020800002003920039118002110910108000010000050202716014272003680000102004020040200402004020040
800242003915003402580010108000010800005064000002002020039200399996031001980010208000020800002003920039118002110910108000010000050202716028212003680000102004020040200402004020040