Apple M1 Microarchitecture Research by Dougall Johnson

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

FCVTXN (scalar, D)

Test 1: uops

Code:

  fcvtxn s0, 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
100430372306125472510001000100039816003018303730372414329141000100010003037303711100110000073116112629100030383038303830383038
10043037259010325472510001000100039816003018303730372414328951000100010003037303711100110000073116112629100030383038303830383038
1004303723576125472510001000100039816003018303730372414328951000100010003037303711100110000073116112629100030383038303830383038
10043037231806125472510001000100039816013018303730372414328951000100010003037303711100110000073116112629100030383038303830383038
10043037231476125472510001000100039816013018303730372414328951000100010003037303711100110000073116112629100030383038303830383038
100430372406125472510001000100039816003018303730372418328951000100010003037303711100110000073116112629100030383038303830383038
100430372206125472510001000100039816013018303730372414328951000100010003037303711100110000073116112629100030383038303830383038
1004303722015625472510001000100039816013018303730372414328951000100010003037303711100110000073116112629100030383038303830383038
100430372206125472510001000100039816013018303730372414328951000100010003037303711100110000073116112629100030383038303830383038
1004303723061254725100010001000398160030183037303724143289510001000100030373037111001100002173116112629100030383038303830383038

Test 2: Latency 1->2

Code:

  fcvtxn s0, 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)030e18191e1f3f4e51inst 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)9fa1a8acc2cfd5d6ddinst fetch restart (de)e0eb? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
10204300372330001206129547251010010010000100100005004277160030018300373003728264328745101002001000020010000300373003711102011009910010010000100000071011611296420100001003003830038300383003830038
1020430037232000006129547251010010010000100100005004277160030018300373003728264328745101002001000020010000300373003711102011009910010010000100000071011611296330100001003003830038300383003830038
1020430037232800906129547251010010010000100100005004277160030018300373003728264328745101002001000020010000300373003711102011009910010010000100000071011611296333100001003003830038300383003830038
1020430037233000006129547251010010010000100100005004277160030018300373003728264328745101002001000020010000300373003711102011009910010010000100000071011611296330100001003003830038300383003830038
1020430037233000006129547251010010010000100100005004277160030018300373003728264328745101002001000020010000300373003711102011009910010010000100000071011611296330100001003003830038300383003830038
1020430037233000006129547251010010010000100100005004277160030018300373003728264328745101002001000020010000300373003711102011009910010010000100000071011611296330100001003003830038300383003830038
10204300372330000064129547251010010010000100100005004277160030018300373003728264328745101002001000020010000300373003711102011009910010010000100000071011611296330100001003003830038300383003830038
1020430037233000006129547251010010010000100100005004277160130018300373003728264328745101002001000020010000300373003711102011009910010010000100000071011611296330100001003003830038300383003830038
10204300372330000010329547251010010010000100100005004277160030018300373003728264328745101002001000020010000300373003711102011009910010010000100000071011611296330100001003003830038300383003830038
1020430037233000006129547251010010010000100100005004277160030018300373003728264328745101002001000020010000300373003711102011009910010010000100000071011611296330100001003003830038300383003830038

1000 unrolls and 10 iterations

Result (median cycles for code): 3.0037

retire (01)cycle (02)0307080b18191e1f3a3f4e51inst 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)9fa1a6a7a8acb1cfd5d6ddinst fetch restart (de)e0? int output thing (e9)? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
10024300372331000021900656229547251001010100001010000504277160130018300373022628300328767100102010000201000030037301791110021109101010000100010006404165529629010000103008430038300383003830038
100243003723300100384006129547251001010100001010000504277160130018300373022628301328841100102210000201065330037300371110021109101010000100000006425165529629010000103003830038300383003830038
100243003723300000519006129547251001010100001010000504277160030018300373003728286328767100102010000201000030037300371110021109101010000100000006405165529629010000103007130038300383003830038
1002430037241000006150061329547441001010100241010000504277160130126300373003728286328767100102010000201000030037300371110021109101010000100000006405164429629010000103003830038300383003830038
1002430037233000000006129547251001010100001010000504277160130018300373003728286328767100102010000201000030037300371110021109101010000100000006406164429629010000103003830038300383003830038
100243003723200000408006129547251001010100001010000504277160030018300373003728286328767100102010000201000030037300371110021109101010000100000006405164629629010000103003830038300383003830038
100243003723300000483006129520601004513100562111650664293384130018300373003728286328767100102010652201000030037300371110021109101010000100200844006405525529629010000103003830038300383003830038
10024300372330000438126406129547251001010100001010000554277160030090300373003728298328767100102010657201000030037300371110021109101010000100000006405164529629010000103003830038300383003830038
10024300372330000000048929547251001010100001010000504277160030018300373003728286328767100102010000201000030037300371110021109101010000100000006404165529629010000103003830038300383003830038
100243003723300000513006129547251001010100001010000504277160130018300373003728286328767100102010000201000030037300371110021109101010000100000006405165629631010000103003830038300383003830038

Test 3: throughput

Count: 8

Code:

  fcvtxn s0, d8
  fcvtxn s1, d8
  fcvtxn s2, d8
  fcvtxn s3, d8
  fcvtxn s4, d8
  fcvtxn s5, d8
  fcvtxn s6, d8
  fcvtxn s7, 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)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)9fa8acc5branch mispredict (cb)cdcfd5d6dde0? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
8020420049155100302580108100800081008002050064013202002020039200399977699908012020080032200800322003920039118020110099100100800001004601115118116020036800001002004020040200402004020040
8020420039155000302580108100800081008002050064013202002020039200399977699908012020080032200800322003920039118020110099100100800001004561115118116020036800001002004020040200402004020040
80204200391560688302580108100800081008002050064013202002020039200399977699908012020080032200800322003920039118020110099100100800001002181115118016020036800001002004020040200402004020040
8020420039155000459258021210080008100801265006401320200202003920039997769990801202008003220080032200392003911802011009910010080000100001115118016020036800001002004020040200402004020040
802042003915500030258010810080008100800205006401320200202003920039997769990801202008003220080032200392003911802011009910010080000100001115118016020036800001002004020040200402004020040
802042003915500030258010810080008100800205006401320200202003920039997769990801202008003220080032200392003911802011009910010080000100001115118016020036800001002004020040200402004020040
8020420039155012030258010810080008100800205006401320200202003920039997769990801202008003220080032200392003911802011009910010080000100001115118016020036800001002004020040200402004020040
80204200391570003672580108100800081008002050064013202002020039200399977699908012020080032200800322003920039118020110099100100800001004231115118016020036800001002004020040200402004020040
8020420039156000229258010810080008100800205006401320200202003920039997769990801202008003220080032200392003911802011009910010080000100101115118016020036800001002004020040200402004020040
802042003915500030258010810080008100800205006401320200202003920039997769990801202008003220080032200392003911802011009910010080000100001115118016020036800001002004020040200402004020040

1000 unrolls and 10 iterations

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

retire (01)cycle (02)0307081e3f51inst 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)9fa7a8acbranch mispredict (cb)cfd0d5d6daddinst fetch restart (de)e0? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
80024200501500004025800101080000108000050640000020020020039200399996310019800102080000208000020039200391180021109101080000100000502004160112003680000102004020040200402004020040
8002420039150011504025800101080000108000050640836020083020099200399996310019800102080000208000020039200391180021109101080000100000502001160112003680000102004020040200402004020040
80024200391500004025800101080000108000050640000020020020039200399996310019800102080000208000020039200391180021109101080000100000502001160112003680000102004020040200402004020040
80024200391500004025800101080000108000050640000020020020039200399996310019800102080000208000020039200391180021109101080000100000502001160112003680000102004020040200402004020040
80024200391500034025800101080000108000050640000020020020039200399996310019800102080000208000020039200391180021109101080000100000502001160112003680000102004020040200402004020040
80024200391500004025800101080000108000050640000020020020039200399996310019800102080000208000020039200391180021109101080000102101502001160112003680000102004020040200402004020040
800242003915000040258001010800001080000506400000200200200392003999963100198001020800002080000200392003911800211091010800001000150502001160112003680000102004020040200402004020040
80024200391500004025800101080000108000050640000020020020039200399996310019800102080000208000020039200391180021109101080000100090502001160112003680000102004020040201422004020040
800242003915000040258010610800001080000506400000200200200392003999963100198001020800002080000200392003911800211091010800001002690502001160112003680000102004020040200402004020040
800242003915000040258001010800001080000506400000200200200392003999963100198001020800002080000200392003911800211091010800001006530502001160112003680000102004020040200402004020040