Apple M1 Microarchitecture Research by Dougall Johnson

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

FCVTZU (vector, fixed-point, 4H)

Test 1: uops

Code:

  fcvtzu v0.4h, v0.4h, #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)03191e3f4e51inst 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
1004303724006125472510001000100039816003018303730372414328951000100010003037303711100110000073116212629100030383038303830383038
10043037230061254725100010001000398160030183037303724143289510001000100030373037111001100001273116122629100030383038303830383038
1004303724007525472510001000100039816003018303730372414328951000100010003037303711100110000073116122629100030383038303830383038
1004303723196125472510001000100039816003018303730372414328951000100010003037303711100110000073116112629100030383038303830383038
1004303723008225472510001000100039816003018303730372414328951000100010003037303711100110000373116122629100030383038303830383038
1004303723006125472510001000100039816003018303730372414328951000100010003037303711100110000073116212629100030383038303830383038
1004303724006125472510001000100039816003018303730372414328951000100010003037303711100110000073116112629100030383038303830383038
1004303723006125472510001000100039816003018303730372414328951000100010003037303711100110000073116122629100030383038303830383038
1004303723008225472510001000100039816003018303730372414328951000100010003037303711100110000073116122629100030383038303830383038
10043037230013725472510001000100039816013018303730372414328951000100010003037303711100110000073116112629100030383038303830383038

Test 2: Latency 1->2

Code:

  fcvtzu v0.4h, v0.4h, #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)0318191e3f4e51inst 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)9fa1a8acbranch mispredict (cb)cdcfd0d5d6ddinst fetch restart (de)e0? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
102043003723300061295472510100100100001001000050042771600300183003730037282643287451010020010000200100003003730037111020110099100100100001000000071002161129633100001003003830038300383003830038
102043003723300061295472510100100100001001000050042771600300183003730037282643287451010020010000200100003003730037111020110099100100100001000000071001161129633100001003003830038300383003830038
102043003723300061295472510100100100001001000050042771600300183003730037282643287451010020010000200100003003730037111020110099100100100001000000071001161129633100001003003830038300383003830038
1020430037233004861295472510100100100001001000050042771600300183003730037282643287451010020010000200100003003730037111020110099100100100001000000071001161129633100001003003830038300383003830038
102043003723300061295472510100100100001001000050042771600300183003730037282643287451010020010000200100003003730037111020110099100100100001000000071001161129633100001003003830038300383003830038
102043003723300061295472510100100100001001000050042771600300183003730037282643287451010020010000200100003003730037111020110099100100100001000001071001161129633100001003003830038300383003830038
1020430037233000103295472510100100100001001000050042771600300183003730037282643287451010020010000200100003003730037111020110099100100100001000000071001161129633100001003003830038300383003830038
1020430037233000631295472510100100100001001000050042771600300183003730037282643287451010020010000200100003003730037111020110099100100100001000000071001161129633100001003003830038300383003830038
102043003723300061295472510100100100001001000050042771600300183003730037282643287451010020010000200100003003730037111020110099100100100001000000071001161129633100001003003830038300383003830038
102043003723200061295472510100100100001001000050042771600300183003730037282643287451010020010000200100003003730037111020110099100100100001000000071001161129633100001003003830038300383003830038

1000 unrolls and 10 iterations

Result (median cycles for code): 3.0037

retire (01)cycle (02)033f4e51inst 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)9fa8accfd5d6ddinst fetch restart (de)e0? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
10024300372256129547251001010100001010000504277160300183003730037282863287671001020100002010000300373003711100211091010100001000640216222962910000103003830038300383003830038
100243003722553629547251001010100001010000504277160300183003730037282863287671001020100002010000300373003711100211091010100001000640216222962910000103003830038300383003830038
10024300372256129547251001010100001010000504277160300183003730037282863287671001020100002010000300373003711100211091010100001000640216222962910000103003830038300383003830038
10024300372256129547251001010100001010000504277160300183003730037282863287671001020100002010000300373003711100211091010100001002925640216222962910000103003830038300383003830038
10024300372256129547251001010100001010000504277160300183003730037282863287671001020100002010000300373003711100211091010100001000640216222962910000103003830038300383003830038
10024300372246129547251001010100001010000504277160300183003730037282863287671001020100002010000300373003711100211091010100001000640216222962910000103003830038300383003830038
10024300372256129547251001010100001010000504277160300183003730037282863287671001020100002010000300373003711100211091010100001000640216222962910000103003830038300383003830038
10024300372256129547251001010100001010000504277631300183003730037282863287671001020100002010000300373003711100211091010100001000640216222962910000103003830038300383003830038
10024300372256129547251001010100001010000504277160300183003730037282863287671001020100002010000300373003711100211091010100001000640216222962910000103003830038300383003830038
10024300372256129547251001010100001010000504277160300183003730037282863287671001020100002010000300373003711100211091010100001000640216222962910000103003830038300383003830038

Test 3: throughput

Count: 8

Code:

  fcvtzu v0.4h, v8.4h, #3
  fcvtzu v1.4h, v8.4h, #3
  fcvtzu v2.4h, v8.4h, #3
  fcvtzu v3.4h, v8.4h, #3
  fcvtzu v4.4h, v8.4h, #3
  fcvtzu v5.4h, v8.4h, #3
  fcvtzu v6.4h, v8.4h, #3
  fcvtzu v7.4h, v8.4h, #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)030b1e3f51inst 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)9fa1a6a8acc5branch mispredict (cb)cdcfd5d6dde0? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
802042005016101353025801081008000810080020500640132120020200392003999776999080120200800322008003220039200391180201100991001008000010000001115118016020036800001002004020040200402004020040
80204200391550022025801081008000810080020500640132120020200392003999776999080120200800322008003220039200391180201100991001008000010000001115118016020036800001002004020040200402004020040
8020420039155003025801081008000810080020500640132120020200392003999776999080120200800322008003220039200391180201100991001008000010000001115118016020036800001002004020040200402004020040
80204200391560123025801081008000810080020500640132120020200392003999776999080120200800322008003220039200391180201100991001008000010010101115118016020036800001002004020040200402004020040
8020420039155063025801081008000810080020500640132120020200392003999776999080120200800322008003220039200391180201100991001008000010000001115118016020036800001002004020040200402004020040
80204200391551153025801081008000810080020500640132120020200392003999776999080120200800322008003220039200391180201100991001008000010000001115118016020036800001002004020040200402004020040
80204200391560183025801081008000810080020500640132120020200392003999776999080120200800322008003220039200391180201100991001008000010000101115118016020036800001002004020040200402004020040
80204200391550123025801081008000810080020500640132120020200392003999776999080120200800322008003220039200391180201100991001008000010000001115118016020036800001002004020040200402004020040
8020420039161005825801081008000810080020500640132120020200392003999776999080120200800322008003220039200391180201100991001008000010000101115118016020036800001002004020040200402004020040
8020420039161003025801081008000810080020500640132120020200392003999776999080120200800322008003220039200391180201100991001008000010000001115118016020036800001002004020040200402004020040

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)9fcfd5d6daddinst fetch restart (de)e0eb? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
80024200511550610518001010800001080000506400000200202003920039999615100198001020800002080000200392003911800211091010800001050201716016620036080000102004020040200402004020040
8002420039156339402580010108000010800005064000002002020039200399996310019800102080000208000020039200391180021109101080000105020616061620036080000102004020040200402004020040
800242003915541198725800101080000108000050640000020020200392003999963100198001020800002080000200392003911800211091010800001050206160161620036080000102004020040200402004020040
80024200391553304025800101080000108000050640000020020200392003999963100198001020800002080000200392003911800211091010800001050201616061620036080000102004020040200402004020040
800242003915504025800101080000108000050640000020020200392003999963100198001020800002080000200392003911800211091010800001050201616016620036080000102004020040200402004020040
80024200391552584025800101080000108000050640000020020200392003999963100198001020800002080000200392003911800211091010800001050201616061620036080000102004020040200402004020040
8002420039155333612580010108000010800005064000012002020039200399996310019800102080000208000020039200391180021109101080000105020616016620036080000102004020040200402004020040
800242003915635713525800101080000108000050640000020020200392003999963100198001020800002080000200392003911800211091010800001050201616013620036080000102004020040200402004020040
800242003915630340258001010800001080000506400000200202003920039999631001980010208000020800002003920039118002110910108000010502016160161620036080000102004020040200402004020040
800242003915532740258001010800001080000506400000200202003920039999631001980010208000020800002003920039118002110910108000010502016160161620036080000102004020040200402004020040