Apple M1 Microarchitecture Research by Dougall Johnson

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

FCVTNS (scalar, H to H)

Test 1: uops

Code:

  fcvtns 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)03080b18191e1f3a3f4e51inst issue (52)~issue fp/simd (54)~dispatch fp/simd (57)huge thing fp/simd (5b)696d6edispatch 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
10043037240000000842547251000100010003981603018303730372414328951000100010003037303711100110000000000073116112629100030383038303830383038
100430372300000001702547251000100010003981603018303730372414328951000100010003037303711100110000000000073116112629100030383038303830383038
10043037230000000612547251000100010003981603018303730372414328951000100010003037303711100110000000000073116112629100030383038303830383038
10043037230000000612547251000100010003981603018303730372414328951000100010003037303711100110000000000073116112629100030383038303830383038
10043037240000000612547251000100010003981603018303730372414328951000100010003037303711100110000000003073116112629100030383038303830383038
10043037240000000612547251000100010003981603018303730372414328951000100010003037303711100110000000100073116112629100030383038303830383038
10043037230000000612547251000100010003981603018303730372414328951000100010003037303711100110000000000073116112629100030383038303830383038
10043037230000000612547251000100010003981603018303730372414328951000100010003037303711100110000000000073116112629100030383038303830383038
1004303724000000061254725100010001000398160305430733084241482907115010001161308530842110011000400112418094124112645100030863085303830853085
100430842400111448805302547431008100011283995123054303730832418729141150116310963084308421100110001000002845073116112664100030853085308530843085

Test 2: Latency 1->2

Code:

  fcvtns 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)0318191e1f3f4e51inst 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)9fa7a8accfd5d6ddinst fetch restart (de)e0? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
1020430037233000089295472510100100100001001000050042771601300183003730037282643287451010020010000200100003003730037111020110099100100100001000007101161129633100001003003830038300383003830038
1020430037233000061295472510100100100001001000050042771601300183003730037282643287451010020010000200100003003730037111020110099100100100001000007101161129633100001003003830038300383003830038
1020430037241000061295472510100100100001001000050042771601300183003730037282643287451010020010000200100003003730037111020110099100100100001000007101161129633100001003003830038300383003830038
1020430037233002717661295472510100100100001001000050042771601300183003730037282643287451010020010000200100003003730037111020110099100100100001000007101161129633100001003003830038300383003830038
1020430037233010061295472510100100100001001000050042771601300183003730037282643287451010020010000200100003003730037111020110099100100100001000007101161129633100001003003830038300383003830038
1020430037233000061295472510100100100001001000050042771601300183003730037282643287451010020010000200100003003730037111020110099100100100001000037101161129633100001003003830038300383003830038
1020430037233000061295472510100100100001001000050042771601300183003730037282643287451010020010000200100003003730037111020110099100100100001000007101161129633100001003003830038300383003830038
1020430037233000061295472510100100100001001000050042771601300183003730037282643287451010020010000200100003003730037111020110099100100100001000007101161129633100001003003830038300383003830038
10204300372330000726295472510100100100001001000050042771601300183003730037282643287451010020010000200100003003730037111020110099100100100001000007101161129633100001003003830038300383003830038
1020430037233000061295472510100100100001001000050042771601300183003730037282643287451010020010000200100003003730037111020110099100100100001000007101161129633100001003003830038300383003830038

1000 unrolls and 10 iterations

Result (median cycles for code): 3.0037

retire (01)cycle (02)0309191e3f4e51inst 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? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
1002430037225000712954725100101010000101000050427716013001830037300372828632876710010201000020100003003730037111002110910101000010000640316222962910000103003830038300383003830038
1002430037225000612954725100101010000101000050427716013001830037300372828632876710010201000020100003003730037111002110910101000010000640216222962910000103003830038300383003830038
1002430037225000612954725100101010000101000050427716013001830037300372828632876710010201000020100003003730037111002110910101000010000640216222962910000103003830038300383003830038
1002430037225000612954725100101010000101000050427716003001830037300372828632876710010201000020100003003730037111002110910101000010000640216222962910000103003830038300383003830038
1002430037225000612954725100101010000101000050427716013001830037300372828632876710010201000020100003003730037111002110910101000010000640216222962910000103003830038300383003830038
1002430037224000612954725100101010000101000050427716013001830037300372828632876710010201000020100003003730037111002110910101000010000640216222962910000103003830038300383003830038
1002430037225000612954725100101010000101000050427716013001830037300372828632876710010201000020100003003730037111002110910101000010000640216222962910000103003830038300383003830038
1002430037225000612954725100101010000101000050427716013001830037300372828632876710010201000020100003003730037111002110910101000010000640216222962910000103003830038300383003830086
1002430037225000612954725100101010000101000050427716013001830037300372828632876710010201000020100003003730037111002110910101000010000640216222962910000103003830038300383003830038
1002430037225000612954725100101010000101000050427716013001830037300372828632876710010201000020100003003730037111002110910101000010200640216222962910000103003830038300383003830038

Test 3: throughput

Count: 8

Code:

  fcvtns h0, h8
  fcvtns h1, h8
  fcvtns h2, h8
  fcvtns h3, h8
  fcvtns h4, h8
  fcvtns h5, h8
  fcvtns h6, h8
  fcvtns 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)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)696d6edispatch 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)9fa6a7a8acc2c5branch mispredict (cb)cdcfd6dde0? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
80204200391560302580108100800081008002050064013220020200392003999776999080120200800322008003220039200391180201100991001008000010000114180111511816020036800001002004020040200402004020040
80204200391550302580108100800081008002050064013220020200392003999776999080120200800322008003220039200391180201100991001008000010000130111511816020036800001002004020040200402004020040
802042003915506952580108100800081008002050064013220020200392003999776999080120200800322008003220039200391180201100991001008000010000100111511816020036800001002004020040200402004020040
80204200391560302580108100800081008002050064013220020200392003999776999080120200800322008003220039200391180201100991001008000010000300111511816020036800001002004020040200402004020040
80204200391553302580108100800081008002050064013220020200392003999776999080120200800322008003220039200391180201100991001008000010000030111511816020036800001002004020040200402004020040
802042003915503025801081008000810080020500640132200202003920039997769990801202008003220080032200392003911802011009910010080000100000390111511816020036800001002004020040200402004020040
80204200391559302580108100800081008002050064013220020200392003999776999080120200800322008003220039200391180201100991001008000010000000111511816020036800001002004020040200402004020040
802042003915503525801081008000810080020500640132200202003920039997769990801202008003220080032200392003911802011009910010080000100003600111511816020036800001002004020040200402004020040
80204200391560302580108100800081008002050064013220020200392003999776999080120200800322008003220039200391180201100991001008000010000500111511816020036800001002004020040200402004020040
80204200391550302580108100800081008002050064013220020200392003999776999080120200800322008003220039200391180201100991001008000010000500111511816020036800001002004020040200402004020040

1000 unrolls and 10 iterations

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

retire (01)cycle (02)030b18191e1f3a3f51inst 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)9fa8accfd0d2d5d6dbddinst fetch restart (de)e0? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
8002420039155000000402580010108000010800005064000000200202003920039999631001980010208000020800002003920039118002110910108000010005020001316011112003680000102004020040200402004020040
80024200391550000004025800101080000108000050640000002002020039200399996310019800102080000208000020039200391180021109101080000100050205241601062003680000102004020040200402004020040
800242003915500030040258001010800001080000506400000020020200392003999963100198001020800002080000200392003911800211091010800001002750205210160572003680000102004020040200402004020040
80024200391550000004025800101080000108000050640000152002020039200399996310019800102080000208000020039200391180021109101080000100050205211160932003680000102004020040200402004020040
800242003915500030040258001010800001080000506400001520020200392003999963100198001020800002080000200392003911800211091010800001002015020536160762003680000102004020040200402004020040
8002420039156000000402580010108000010800005064000015200202003920039999631001980010208000020800002003920039118002110910108000010005020537160642003680000102004020040200402004020040
80024200391550000004025800101080000108000050640000002002020039200399996310019800102080000208000020039200391180021109101080000101050200051607132003680000102004020040200402004020040
800242003915500042006925800101080000108000050640000002002020039200399996310019800102080000208000020039200391180021109101080000100395020006160662003680000102004020040200402004020040
800242003915500012006825800101080000108000050640000002002020039200399996310019800102080000208000020039200391180021109101080000100050200041605112003680000102004020040200402004020040
8002420039161000000402580010108000010800005064000000200202003920039999631001980010208000020800002003920039118002110910108000010005020001016010102003680000102004020040200402004020040