Apple M1 Microarchitecture Research by Dougall Johnson

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

FCVTNU (vector, 2S)

Test 1: uops

Code:

  fcvtnu v0.2s, v0.2s
  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)03081e3f4e51inst 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
1004303724006125472510001000100039816003018303730372414328951000100010003037303711100110000073116112629100030383038303830383038
1004303724006125472510001000100039816013018303730372414328951000100010003037303711100110000073116112629100030383038303830383038
1004303724006125472510001000100039816003018303730372414328951000100010003037303711100110000073116112629100030383038303830383038
1004303724006125472510001000100039816013018303730372414328951000100010003037303711100110000073116112629100030383038303830383038
1004303724006125472510001000100039816013018303730372414328951000100010003037303711100110000073116112629100030383038303830383038
10043037240010325472510001000100039816003018303730372414328951000100010003037303711100110000073116112629100030383038303830383038
1004303724006125472510001000100039816003018303730372414328951000100010003037303711100110000073116112629100030383038303830383038
10043037230015625472510001000100039816013018303730372414328951000100010003037303711100110000073116112629100030383038303830383038
1004303723006125472510001000100039816003018303730372414328951000100010003037303711100110000073116112629100030383038303830383038
1004303723006125472510001000100039816003018303730372414328951000100010003037303711100110000073116112629100030383038303830383038

Test 2: Latency 1->2

Code:

  fcvtnu v0.2s, v0.2s
  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)9fa8acc5branch mispredict (cb)cdcfd5d6ddinst fetch restart (de)e0ec? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
10204300372320441295472510100100100001001000050042771600300183003730037282716287411010020010008200100083003730037111020110099100100100001000011171701611296330100001003003830038300383003830086
1020430037233061295472510100100100001001000050042771600300183003730037282643287451010020010000200100003003730037111020110099100100100001000000071011611296330100001003003830038300383003830038
1020430037232061295472510100100100001001000050042771600300183003730037282643287451010020010000200100003003730037111020110099100100100001000000071011611296330100001003003830038300383003830038
1020430037232061295472510100100100001001000050042771600300183003730037282643287451010020010000200100003003730037111020110099100100100001000000071011611296330100001003003830038300383003830038
10204300372330318295472510100100100001001000050042771600300183003730037282643287451010020010000200100003003730037111020110099100100100001000000071011611296330100001003003830038300383003830038
102043003723301539295472510100100100001001000050042771600300183003730037282643287451010020010000200100003003730037111020110099100100100001000000071011611296330100001003003830038300863003830038
1020430037233061295472510100100100001001000050042771600300183003730037282643287451010020010000200100003003730037111020110099100100100001000010071011611296330100001003003830038300383003830038
1020430037241061295472510100100100001001000050042771600300183003730037282643287451010020010000200100003003730037111020110099100100100001000000071011611296330100001003003830038300383003830038
10204300372320107295472510100100100001001000050042771600300183003730037282643287451010020010000200100003003730037111020110099100100100001000000071011611296330100001003003830038300383003830038
1020430037233061295472510100100100001001014850042771600300183003730037282643287451010020010000200100003003730037111020110099100100100001000000071011611296331100001003003830038300383003830038

1000 unrolls and 10 iterations

Result (median cycles for code): 3.0037

retire (01)cycle (02)03181e3f4e51inst 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)9fa8accfd5d6daddinst fetch restart (de)e0? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
1002430037233015612954725100101010000101000050427716003001830037300372828632877710010201000020100003003730037111002110910101000010006402160222962910000103003830038300383003830038
100243003722400612954725100101010000101000050427716003001830037300372828632876710010201000020100003003730037111002110910101000010006402160222962910000103003830038300383003830038
100243003722400612954725100101010000101000050427716003001830037300372828632876710010201000020100003003730037111002110910101000010006402160222962910000103003830038300383003830038
100243003722500612954725100101010000101000050427716013001830037300372828632876710010201000020100003003730037111002110910101000010006402160222962910000103003830038300383003830038
100243003722500612954725100101010000101000050427716003001830037300372828632876710010201000020100003003730037111002110910101000010006402160222962910000103003830038300383003830038
100243003722500612954725100101010000101000050427716003001830037300372828632876710010201000020100003003730037111002110910101000010006402160222962910000103003830038300383003830038
100243003723300612954725100101010000101000050427716013001830037300372828632876710010201000020100003003730037111002110910101000010006401240222962910000103003830038300383003830038
100243003722500612954725100101010000101000050427716003001830037300372828632876710010201000020100003003730037111002110910101000010006402160222962910000103003830038300383003830038
100253003722500612954725100101010000101000050427716003001830037300372828632876710010201000020100003003730037111002110910101000010006402160222962910000103003830038300383003830038
100243003722500612954725100101010000101014950427716003001830037300372828632876710010201000020100003003730037111002110910101000010006402160222962910000103003830038300383003830038

Test 3: throughput

Count: 8

Code:

  fcvtnu v0.2s, v8.2s
  fcvtnu v1.2s, v8.2s
  fcvtnu v2.2s, v8.2s
  fcvtnu v3.2s, v8.2s
  fcvtnu v4.2s, v8.2s
  fcvtnu v5.2s, v8.2s
  fcvtnu v6.2s, v8.2s
  fcvtnu v7.2s, v8.2s
  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)0318191e1f3f51inst 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)9fa1a6a8a9acc5branch mispredict (cb)cdcfd5d6ddinst fetch restart (de)e0? int output thing (e9)? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
8020420059155000030258010810080008100800205006401320200202003920039997706999080120200800322008003220039200391180201100991001008000010000000111511821600200360800001002004020040200402004020040
8020420039155000030258010810080008100800205006401320200202003920039997706999080120200800322008003220039200391180201100991001008000010000000111511801600200360800001002004020040200402004020040
8020420039155000072258010810080008100800205006401320200202003920039997706999080120200800322008003220039200391180201100991001008000010000000111511801601200360800001002004020040200402004020040
8020420039155400030258010810080008100800205006401320200202003920039997706999080120200800322008003220039200391180201100991001008000010000000111511801610200360800001002004020040200402004020040
8020420039155000030258010810080008100800205006401320200202003920039997706999080120200800322008003220039200393180201100991001008000010000000111511801600200360800001002004020040200402004020040
8020420039156000030258010810080008100800205006401320200202003920039997706999080120200800322008003220039200391180201100991001008000010000000111511801600200360800001002004020040200402004020040
8020420039155000030258010810080008100800205006401320200202003920039997706999080120200800322008003220039200391180201100991001008000010000000111511801600200360800001002004020040200402004020040
80204200391550039030258010810080008100800205006434480200202003920039997706999080120200800322008003220039200391180201100991001008000010000000111511801600200360800001002004020040200402004020040
802042003915600451321425258010810080008100800205006401320200202003920039997706999080120202800322008003220039200391180201100991001008000010000100111511801600200360800001002004020040200402004020040
80204200391550000695258010810080008100800205006401320200202003920039997706999080120200800322008003220039200391180201100991001008000010000000111511801600200360800001002004020040200402004020040

1000 unrolls and 10 iterations

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

retire (01)cycle (02)03090b18191e3f51inst 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)9fa8accfd0d2icache miss (d3)d5d6d9ddinst fetch restart (de)e0eaeb? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
80024200501550000514025800101080000108000050640000020020200392003999963100198001020800002080000200392003911800211091010800001000502000016160616200360080000102004020040200402004020040
8002420039155000028840258001010800001080000506400000200202003920039999631001980010208000020800002003920039118002110910108000010005020000171601717200360080000102004020040200402004020040
8002420039156000104025800101080000108000050640000020020200392003999963100198001020800002080000200392003911800211091010800001000502000017160176200360080000102004020040200402004020040
800242003915600003004025800101080000108000050640000020020200392003999963100198001020800002080000200392003911800211091010800001000502000017160176200360080000102004020040200402004020040
800242003915600002974025800101080000108000050640000020020200392003999963100198001020800002080000200392003911800211091010800001000502000017160178200360080000102004020040200402004020040
800242003915500002792302580010108000010800005064000002002020039200399996310019800102080000208000020039200391180021109101080000100050200008160617200360080000102004020040200402004020040
80024200391550000214025800101080000108000050640000020020200392003999963100198001020800002080000200392003911800211091010800001000502000017160178200360080000102004020040200402004020040
800242003915600000402580010108000010800005064000002002020039200399996310019800102080000208000020039200391180021109101080000100050200006160177200360080000102004020040200402004020040
8002420039155000004025800101080000108000050640000020020200392003999963100198001020800002080000200392003911800211091010800001000502000017160157200360080000102004020040200402004020040
80024200391550000318402580010108000010800005064000002002020039200399996310019800102080000208000020039200391180021109101080000100050200006160176200360080000102004020040200402004020040