Apple M1 Microarchitecture Research by Dougall Johnson

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

FCVTZS (scalar, fixed-point, D to D)

Test 1: uops

Code:

  fcvtzs d0, d0, #3
  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)a1a8accfd5d6ddinst fetch restart (de)e0? fp/simd (ee)f5f6f7f8fd
1004303724061254725100010001000398160030183037303724143289510001000100030373037111001100000073116112629100030383038303830383038
1004303724061254725100010001000398160130183037303724143289510001000100030373037111001100000073116112629100030383038303830383038
1004303724061254725100010001000398160130183037303724143289510001000100030373037111001100000073116112629100030383038303830383038
1004303724061254725100010001000398160030183037303724143289510001000100030373037111001100000073116112642100030383038303830383038
1004303724061254725100010001000398160130183037303724143289510001000100030373037111001100000073116112629100030383038303830383038
1004303723061254725100010001000398160030183037303724143289510001000100030373037111001100000073116112629100030383038303830383038
1004303724061254725100010001000398160130183037303724143289510001000100030373037111001100000073116112629100030383038303830383038
1004303723061254725100010001000398160130183037303724143289510001000100030373037111001100000073116112629100030383038303830383038
1004303723082254725100010001000398160030183037303724143289510001000100030373037111001100000373116112629100030383038303830383038
1004303724084254725100010001000398160030183037303724143289510001000100030373037111001100000073116112629100030383038303830383038

Test 2: Latency 1->2

Code:

  fcvtzs d0, d0, #3
  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)9fa0a8accfd5d6ddinst fetch restart (de)e0? int output thing (e9)? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
102043003723327612954725101001001000010010000500427716003001830037300372826432874510100200100002001000030037300371110201100991001001000010000071011611296330100001003003830038300383003830038
10204300372320612954725101001001000010010000500427716003001830037300372826432874510100200100002001000030037300371110201100991001001000010000071011611296330100001003003830038300383003830038
1020430037232154612954725101001001000010010000500427716013001830037300372826432874510100200100002001000030037300371110201100991001001000010000071011611296330100001003003830038300383003830038
102043003723301032954725101001001000010010000500427716013001830180300372826432874510100200100002001000030037300371110201100991001001000010020371011611296330100001003003830038300383003830038
102043003723301032954725101001001000010010000500427716003001830037300372826432874510100200100002001000030037300371110201100991001001000010000071011611296330100001003003830038300383003830038
10204300372330612954725101001001000010010000500427716013001830037300372826432874510100200100002001000030037300371110201100991001001000010000071011611296330100001003003830038300383003830038
10204300372330612954725101001001000010010000500427716013001830037300372826432874510100200100002001000030037300371110201100991001001000010000071011611296330100001003003830038300383003830038
102043003723318612954725101001001000010010000500427716013012630037300372826432874510100200100002001000030037300371110201100991001001000010000071011611296330100001003003830038300383003830038
102043003723336612954725101001001000010010000500427716013001830037300372826432874510100200100002001000030037300371110201100991001001000010000071011611296330100001003003830038300383003830038
10204300372330612954725101001001000010010000500427716003001830037300372826432874510100200100002001000030037300371110201100991001001000010000071011611296330100001003003830038300383003830038

1000 unrolls and 10 iterations

Result (median cycles for code): 3.0037

retire (01)cycle (02)03080b18191e1f3a3f4e51inst 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)6061696d6edispatch 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)9fa0a1a6a8a9acc2cdcfd0d2d5d6ddinst fetch restart (de)e0? int output thing (e9)? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
10024300372320000000612954725100101010000101000050427716000300183003730037282863287671001020100002010000300373003711100211091010100001000000000640002162229629010000103003830038300383003830038
10024300372330000000612954725100101010000101000050427716000300183003730037282863287671001020100002010000300373003711100211091010100001010000000640002162229629010000103003830038300383003830038
10024300372330000000612954725100101010000101000050427716000300183003730037282863287671001020100002010000300373003711100211091010100001000000288000640002162229629010000103003830038300383003830038
10024300372330000000612954725100101010000101000050427716000300183003730037282863287671001020100002010000300373003711100211091010100001000000000640002162229629010000103003830038300383003830038
10024300372330000000612954725100101010000101000050427716000300183003730037282863287671001020100002010000300373003711100211091010100001000000000640002162229629010000103003830038300383003830038
10024300372330000000612954725100101010000101000050427716000300183003730037282863287671001020100002010000300373003711100211091010100001000000000640002162229629010000103003830038300383003830038
10024300372320000000612954725100101010000101000050427716000300183003730037282863287671001020100002010000300373003711100211091010100001000000000640002162229629010000103003830038300383003830038
10024300372330000000612954725100101010000101000050427716000300183003730037282863287671061320100002010000300373003711100211091010100001000000000640002162229699010000103003830038300383003830038
10024300372330000000612954725100101010000101000050427716000300183003730037282863287671001020100002010000300373003711100211091010100001000000000640002162229629010000103003830038300383003830038
10024300372250000000612954725100101010000101000050427716000300183003730037282863287671001020100002010000300373003711100211091010100001000000000640002162229629010000103003830038300383003830038

Test 3: throughput

Count: 8

Code:

  fcvtzs d0, d8, #3
  fcvtzs d1, d8, #3
  fcvtzs d2, d8, #3
  fcvtzs d3, d8, #3
  fcvtzs d4, d8, #3
  fcvtzs d5, d8, #3
  fcvtzs d6, d8, #3
  fcvtzs d7, d8, #3
  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)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)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)9fa0a8acc5branch mispredict (cb)cdcfd5d6ddinst fetch restart (de)e0? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
80204200581550003025801081008000810080020500640132020020200392003999776999080120200800322008003220039200391180201100991001008000010000311151180160020036800001002004020040200402004020040
80204200391550003025801081008000810080020500640132020020200392003999776999080120200800322008003220039200391180201100991001008000010000011151180160020036800001002004020040200402004020040
80204200391550003025801081008000810080020500640132020020200392003999776999080120200800322008003220039200391180201100991001008000010000011151180160020036800001002004020040200402007620040
8020420039156002153625801081008000810080020500640132020020200392003999776999080120200800322008003220039200391180201100991001008000010000011151180160020036800001002004020040200402004020040
80204200391550003025801081008000810080020500640132020020200392003999776999080120200800322008003220039200391180201100991001008000010000011151180160020036800001002004020040200402004020040
80204200391550003025801081008000810080020500640132020020200392003999776999080120200800322008003220039200391180201100991001008000010000011151180160020036800001002004020040200402004020040
80204200391550004025801081008000810080020500640132020020200392003999776999080120200800322008003220077200391180201100991001008000010000011151180160020036800001002004020040200402004020040
80204200391550003025801081008000810080020500640132020020200392003999776999080120200800322008003220039200391180201100991001008000010000011151180160020036800001002004020040200402004020040
80204200391550003025801081008000810080020500640132020020200392003999776999080120200800322008003220039200391180201100991001008000010000011151180160020036800001002004020040200402004020040
80204200391550003025801081008000810080020500640132020020200392003999776999080120200800322008003220039200391180201100991001008000010000011151180160020086800001002004020040200402004020040

1000 unrolls and 10 iterations

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

retire (01)cycle (02)031e3f51inst 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)9fa8abaccfd5d6dbddinst fetch restart (de)e0? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
800242003915564025800101080000108000050640000120020200392003999963100198001020800002080000200392003911800211091010800001000050206160222003680000102004020040200402004020040
800242003915504025800101080000108000050640000120020200392003999963100198001020800002080000200392003911800211091010800001000050203160262003680000102004020040200402004020040
8002420039155244025800101080000108000050640000120020200392003999963100198001020800002080000200392003911800211091010800001000050202160222003680000102004020040200402004020040
800242003915604025800101080000108000050640000120020200392003999963100198001020800002080000200392003911800211091010800001000350202160222003680000102004020040200402004020040
8002420039155040258001010800001080000506400001200202003920039100053100198001020801042080000200392003911800211091010800001000050206160362003680000102004020040200402004020040
8002420039155032525800101080000108000050640000120020200392003999963100198001020800002080000200392003911800211091010800001000050202160222003680000102004020040200402009020040
8002420039155364025800101080000108000050640000120020200392003999963100198001020800002080000200392003911800211091010800001000050202160662003680000102004020040200402004020040
800242003915504025800101080000108000050640000120020200392003999963100198001020800002080000200392003911800211091010800001000050202160622003680000102004020040200402004020040
8002420039155154025800101080000108000050640000120020200392003999963100198001020800002080000200392003911800211091010800001000050202160632003680000102004020040200402004020040
8002420039155082258001010800001080000506400001200202024120039999631001980010208000020800002003920039118002110910108000010015050202160222003680000102004020040200402004020040