Review Memory Disambiguation Review Explicit Register Renaming

5HYLHZꢊꢉ5HRUGHUꢉ%XIIHUꢉꢍ52%ꢎ &6ꢀꢁꢀ *UDGXDWHꢉ&RPSXWHUꢉ$UFKLWHFWXUH /HFWXUHꢉꢃ ‡ 8VHꢉRIꢉUHRUGHUꢉEXIIHU ² ,QꢏRUGHUꢉLVVXHꢌꢉ2XWꢏRIꢏRUGHUꢉH[HFXWLRQꢌꢉ,QꢏRUGHUꢉFRPPLW ² +ROGVꢉUHVXOWVꢉXQWLOꢉWKH\ꢉFDQꢉEHꢉFRPPLWWHGꢉLQꢉRUGHU ª 6HUYHVꢉDVꢉVRXUFHꢉRIꢉYDOXHVꢉXQWLOꢉLQVWUXFWLRQVꢉFRPPLWWHG ,QVWUXFWLRQꢉ/HYHOꢉ3DUDOOHOLVPꢊ *HWWLQJꢉWKHꢉ&3,ꢉꢋꢉꢅ ² 3URYLGHVꢉVXSSRUWꢉIRUꢉSUHFLVHꢉH[FHSWLRQVꢂ6SHFXODWLRQꢊꢉVLPSO\ꢉWKURZꢉRXWꢉ LQVWUXFWLRQVꢉODWHUꢉWKDQꢉH[FHSWHGꢉLQVWUXFWLRQꢄ ² &RPPLWVꢉXVHUꢏYLVLEOHꢉVWDWHꢉLQꢉLQVWUXFWLRQꢉRUGHU ² 6WRUHVꢉVHQWꢉWRꢉPHPRU\ꢉV\VWHPꢉRQO\ꢉZKHQꢉWKH\ꢉUHDFKꢉKHDGꢉRIꢉEXIIHU 6HSWHPEHUꢉꢀꢇꢌꢉꢀꢈꢈꢈ 3URIꢄꢉ-RKQꢉ.XELDWRZLF] ‡ ,Qꢏ2UGHUꢏ&RPPLW LVꢉLPSRUWDQWꢉEHFDXVHꢊ ² $OORZVꢉWKHꢉJHQHUDWLRQꢉRIꢉSUHFLVHꢉH[FHSWLRQV ² $OORZVꢉVSHFXODWLRQꢉDFURVVꢉEUDQFKHV &6ꢀꢁꢀꢂ.XELDWRZLF] /HF ꢃꢄꢅ &6ꢀꢁꢀꢂ.XELDWRZLF] <ul style="display: flex;"><li style="flex:1">ꢆꢂꢀꢇꢂꢈꢈ </li><li style="flex:1">ꢆꢂꢀꢇꢂꢈꢈ </li></ul>/HF ꢃꢄꢀ 5HYLHZꢊꢉ0HPRU\ꢉ'LVDPELJXDWLRQ 5HYLHZꢊꢉ([SOLFLWꢉ5HJLVWHUꢉ5HQDPLQJ ‡ 0DNHꢉXVHꢉRIꢉDꢉSK\VLFDO UHJLVWHUꢉILOHꢉWKDWꢉLVꢉODUJHUꢉWKDQꢉ ‡ 4XHVWLRQꢊꢉ*LYHQꢉDꢉORDGꢉWKDWꢉIROORZVꢉDꢉVWRUHꢉLQꢉSURJUDPꢉ QXPEHUꢉRIꢉUHJLVWHUVꢉVSHFLILHGꢉE\ꢉ,6$ RUGHUꢌꢉDUHꢉWKHꢉWZRꢉUHODWHG" ² 7U\LQJꢉWRꢉGHWHFWꢉ5$:ꢉKD]DUGVꢉWKURXJKꢉPHPRU\ꢉ ‡ .H\ꢉLQVLJKWꢊꢉ$OORFDWHꢉDꢉQHZꢉSK\VLFDOꢉGHVWLQDWLRQꢉUHJLVWHUꢉ ² 6WRUHVꢉFRPPLWꢉLQꢉRUGHUꢉꢍ52%ꢎꢌꢉVRꢉQRꢉ:$5ꢂ:$:ꢉPHPRU\ꢉKD]DUGVꢄ IRUꢉHYHU\ꢉLQVWUXFWLRQꢉWKDWꢉZULWHV ² 5HPRYHVꢉDOOꢉFKDQFHꢉRIꢉ:$5ꢉRUꢉ:$:ꢉKD]DUGV ‡ ,PSOHPHQWDWLRQꢉ ² 6LPLODUꢉWRꢉFRPSLOHUꢉWUDQVIRUPDWLRQꢉFDOOHGꢉ6WDWLFꢉ6LQJOHꢉ$VVLJQPHQW ª /LNHꢉKDUGZDUHꢏEDVHGꢉG\QDPLFꢉFRPSLODWLRQ" ² .HHSꢉTXHXHꢉRIꢉVWRUHVꢌꢉLQꢉSURJꢉRUGHU ² :DWFKꢉIRUꢉSRVLWLRQꢉRIꢉQHZꢉORDGVꢉUHODWLYHꢉWRꢉH[LVWLQJꢉVWRUHV ‡ 0HFKDQLVP"ꢉꢉ.HHSꢉDꢉWUDQVODWLRQꢉWDEOHꢊ ² ,6$ꢉUHJLVWHUꢉ⇒ SK\VLFDOꢉUHJLVWHUꢉPDSSLQJ ‡ :KHQꢉKDYHꢉDGGUHVVꢉIRUꢉORDGꢌꢉFKHFNꢉVWRUHꢉTXHXHꢊ ² ,IꢉDQ\ VWRUHꢉSULRUꢉWRꢉORDGꢉLVꢉZDLWLQJꢉIRUꢉLWVꢉDGGUHVVꢌꢉVWDOOꢉORDGꢄ ² :KHQꢉUHJLVWHUꢉZULWWHQꢌꢉUHSODFHꢉHQWU\ꢉZLWKꢉQHZꢉUHJLVWHUꢉIURPꢉIUHHOLVWꢄ ² 3K\VLFDOꢉUHJLVWHUꢉIUHHꢉZKHQꢉQRWꢉXVHGꢉE\ꢉDQ\ꢉDFWLYHꢉLQVWUXFWLRQV ² ,IꢉORDGꢉDGGUHVVꢉPDWFKHVꢉHDUOLHUꢉVWRUHꢉDGGUHVVꢉꢍDVVRFLDWLYHꢉORRNXSꢎꢌꢉ WKHQꢉZHꢉKDYHꢉDꢉPHPRU\ꢀLQGXFHGꢁ5$:ꢁKD]DUGꢊ ª VWRUHꢉYDOXHꢉDYDLODEOHꢉ⇒ UHWXUQꢉYDOXH ª VWRUHꢉYDOXHꢉQRWꢉDYDLODEOHꢉ⇒ UHWXUQꢉ52%ꢉQXPEHUꢉRIꢉVRXUFHꢉ ² 2WKHUZLVHꢌꢉVHQGꢉRXWꢉUHTXHVWꢉWRꢉPHPRU\ ‡ $GYDQWDJHVꢉRIꢉH[SOLFLWꢉUHQDPLQJꢊ ² 'HFRXSOHVꢉUHQDPLQJ IURPꢉVFKHGXOLQJꢀ ² $OORZVꢉGDWDꢉWRꢉEHꢉIHWFKHGꢉIURPꢉVLQJOHꢉUHJLVWHUꢉILOH ª 1RꢉQHHGꢉWRꢉE\SDVVꢉYDOXHVꢉIURPꢉUHRUGHUꢉEXIIHU ‡ :LOOꢉUHOD[ꢉH[DFWꢉGHSHQGHQF\ꢉFKHFNLQJꢉLQꢉODWHUꢉOHFWXUH ª %HWWHUꢉXWLOL]DWLRQꢉRIꢉUHJLVWHUꢉSRUWV &6ꢀꢁꢀꢂ.XELDWRZLF] /HF ꢃꢄꢐ &6ꢀꢁꢀꢂ.XELDWRZLF] <ul style="display: flex;"><li style="flex:1">ꢆꢂꢀꢇꢂꢈꢈ </li><li style="flex:1">ꢆꢂꢀꢇꢂꢈꢈ </li></ul>/HF ꢃꢄꢑ *HWWLQJꢉ&3,ꢉꢋꢉꢅꢊꢉ,VVXLQJ 0XOWLSOHꢉ,QVWUXFWLRQVꢂ&\FOH ‡ 6XSHUVFDODUꢊꢉYDU\LQJꢉQRꢄꢉLQVWUXFWLRQVꢂF\FOHꢉꢍꢅꢉWRꢉ ꢃꢎꢌꢉVFKHGXOHGꢉE\ꢉFRPSLOHUꢉRUꢉE\ꢉ+:ꢉꢍ7RPDVXORꢎ ² ,%0ꢉ3RZHU3&ꢌꢉ6XQꢉ8OWUD6SDUFꢌꢉ'(&ꢉ$OSKDꢌꢉ+3ꢉꢃꢈꢈꢈ ,QVWUXFWLRQꢉ/HYHOꢉ3DUDOOHOLVP ‡ +LJKꢉVSHHGꢉH[HFXWLRQꢉEDVHGꢉRQꢉLQVWUXFWLRQ OHYHO SDUDOOHOLVP ꢍLOSꢎꢊꢉSRWHQWLDOꢉRIꢉVKRUWꢉ LQVWUXFWLRQꢉVHTXHQFHVꢉWRꢉH[HFXWHꢉLQꢉSDUDOOHO ‡ ꢍ9HU\ꢎꢉ/RQJꢉ,QVWUXFWLRQꢉ:RUGVꢉꢍ9ꢎ/,:ꢊꢉ IL[HGꢉQXPEHUꢉRIꢉLQVWUXFWLRQVꢉꢍꢑꢏꢅꢒꢎꢉVFKHGXOHGꢉ E\ꢉWKHꢉFRPSLOHUꢓꢉSXWꢉRSVꢉLQWRꢉZLGHꢉWHPSODWHV ² -RLQWꢉ+3ꢂ,QWHOꢉDJUHHPHQWꢉLQꢉꢅꢆꢆꢆꢂꢀꢈꢈꢈ" ‡ +LJKꢏVSHHGꢉPLFURSURFHVVRUVꢉH[SORLWꢉ,/3ꢉE\ꢊ ꢅꢎꢉSLSHOLQHGꢉH[HFXWLRQꢊꢉRYHUODSꢉLQVWUXFWLRQV ² ,QWHOꢉ$UFKLWHFWXUHꢏꢒꢑꢉꢍ,$ꢏꢒꢑꢎꢉꢒꢑꢏELWꢉDGGUHVV ꢀꢎꢉ2XWꢏRIꢏRUGHUꢉH[HFXWLRQꢉꢍFRPPLWꢉLQꢏRUGHUꢎ ª 6W\OHꢊꢉ´([SOLFLWO\ꢉ3DUDOOHOꢉ,QVWUXFWLRQꢉ&RPSXWHUꢉꢍ(3,&ꢎµ ² 1HZꢉ681ꢉ0$-,&ꢉ$UFKLWHFWXUHꢊꢉ9/,:ꢉIRUꢉ-DYD ꢐꢎꢉ0XOWLSOHꢉLVVXHꢊꢉLVVXHꢉDQGꢉH[HFXWHꢉPXOWLSOHꢉ LQVWUXFWLRQVꢉSHUꢉFORFNꢉF\FOH ‡ 9HFWRUꢉ3URFHVVLQJꢊ ꢑꢎꢉ9HFWRUꢉLQVWUXFWLRQVꢊꢉPDQ\ꢉLQGHSHQGHQWꢉRSVꢉVSHFLILHGꢉ ZLWKꢉDꢉVLQJOHꢉLQVWUXFWLRQ ([SOLFLWꢉFRGLQJꢉRIꢉLQGHSHQGHQWꢉORRSVꢉDVꢉ RSHUDWLRQVꢉRQꢉODUJHꢉYHFWRUVꢉRIꢉQXPEHUV ² 0XOWLPHGLDꢉLQVWUXFWLRQVꢉEHLQJꢉDGGHGꢉWRꢉPDQ\ꢉSURFHVVRUV ‡ 0HPRU\ꢉDFFHVVHVꢉIRUꢉKLJKꢏVSHHGꢉ PLFURSURFHVVRU" ‡ $QWLFLSDWHGꢉVXFFHVVꢉOHDGꢉWRꢉXVHꢉRIꢉ ²'DWDꢉ&DFKHꢉSRVVLEO\ꢉPXOWLSRUWHGꢌꢉPXOWLSOHꢉOHYHOV ,QVWUXFWLRQVꢉ3HUꢉ&ORFN F\FOHꢉꢍ,3&ꢎꢉYVꢄꢉ&3, &6ꢀꢁꢀꢂ.XELDWRZLF] /HF ꢃꢄꢁ &6ꢀꢁꢀꢂ.XELDWRZLF] /HF ꢃꢄꢒ <ul style="display: flex;"><li style="flex:1">ꢆꢂꢀꢇꢂꢈꢈ </li><li style="flex:1">ꢆꢂꢀꢇꢂꢈꢈ </li></ul>*HWWLQJꢉ&3,ꢉꢋꢉꢅꢊꢉ,VVXLQJ 5HYLHZꢊꢉ8QUROOHGꢉ/RRSꢉWKDWꢉ 0LQLPL]HVꢉ6WDOOVꢉIRUꢉ6FDODU 0XOWLSOHꢉ,QVWUXFWLRQVꢂ&\FOH ‡ 6XSHUVFDODU '/;ꢊꢉꢀꢉLQVWUXFWLRQVꢌꢉꢅꢉ)3ꢉIꢉꢅꢉDQ\WKLQJꢉ 1 Loop: LD F0,0(R1) LD to ADDD: 1 Cycle ADDD to SD: 2 Cycles HOVH 234LD LD LD F6,-8(R1) F10,-16(R1) F14,-24(R1) ² )HWFKꢉꢒꢑꢏELWVꢂFORFNꢉF\FOHꢓꢉ,QW RQꢉOHIWꢌꢉ)3ꢉRQꢉULJKW ² &DQꢉRQO\ꢉLVVXHꢉꢀQGꢉLQVWUXFWLRQꢉLIꢉꢅVWꢉLQVWUXFWLRQꢉLVVXHV ² 0RUHꢉSRUWVꢉIRUꢉ)3ꢉUHJLVWHUVꢉWRꢉGRꢉ)3ꢉORDGꢉIꢉ)3ꢉRSꢉLQꢉDꢉSDLU 5678ADDD F4,F0,F2 ADDD F8,F6,F2 ADDD F12,F10,F2 ADDD F16,F14,F2 <ul style="display: flex;"><li style="flex:1">7\SH </li><li style="flex:1">3LSH6WDJHV </li></ul>,QWꢄꢉLQVWUXFWLRQ )3ꢉLQVWUXFWLRQ ,QWꢄꢉLQVWUXFWLRQ )3ꢉLQVWUXFWLRQ ,QWꢄꢉLQVWUXFWLRQ )3ꢉLQVWUXFWLRQ ,) ,' (; 0(0 :% ,) ,' (; 0(0 :% ,) ,' (; 0(0 :% ,) ,' (; 0(0 :% ,) ,' (; 0(0 :% ,) ,' (; 0(0 :% 9SD SD SD 0(R1),F4 -8(R1),F8 -16(R1),F12 10 11 12 13 14 SUBI R1,R1,#32 BNEZ R1,LOOP <ul style="display: flex;"><li style="flex:1">SD </li><li style="flex:1">8(R1),F16 </li></ul>; 8-32 = -24 ‡ꢅꢉF\FOHꢉORDGꢉGHOD\ꢉH[SDQGVꢉWRꢉꢐꢉLQVWUXFWLRQV LQꢉ66 14 clock cycles, or 3.5 per iteration ² LQVWUXFWLRQꢉLQꢉULJKWꢉKDOIꢉFDQ·WꢉXVHꢉLWꢌꢉQRUꢉLQVWUXFWLRQVꢉLQꢉQH[W &V6OꢀRꢁꢀWꢂ.XELDWRZLF] &6ꢀꢁꢀꢂ.XELDWRZLF] /HF ꢃꢄꢃ <ul style="display: flex;"><li style="flex:1">ꢆꢂꢀꢇꢂꢈꢈ </li><li style="flex:1">ꢆꢂꢀꢇꢂꢈꢈ </li></ul>/HF ꢃꢄꢇ '\QDPLFꢉ6FKHGXOLQJꢉLQꢉ6XSHUVFDODU 7KHꢉHDV\ꢉZD\ /RRSꢉ8QUROOLQJꢉLQꢉ6XSHUVFDODU ,QWHJHUꢁLQVWUXFWLRQ /'ꢉꢉꢉꢉ)ꢈꢌꢈꢍ5ꢅꢎ <ul style="display: flex;"><li style="flex:1">)3ꢁLQVWUXFWLRQ </li><li style="flex:1">&ORFNꢁF\FOH </li></ul><ul style="display: flex;"><li style="flex:1">/RRSꢊ </li><li style="flex:1">ꢅ</li></ul>ꢀꢐꢑꢁꢒꢇꢃꢆ‡ +RZꢉWRꢉLVVXHꢉWZRꢉLQVWUXFWLRQVꢉDQGꢉNHHSꢉLQꢏRUGHUꢉ /'ꢉꢉꢉꢉ)ꢒꢌꢏꢃꢍ5ꢅꢎ /'ꢉꢉꢉꢉ)ꢅꢈꢌꢏꢅꢒꢍ5ꢅꢎ /'ꢉꢉꢉꢉ)ꢅꢑꢌꢏꢀꢑꢍ5ꢅꢎ /'ꢉꢉꢉꢉ)ꢅꢃꢌꢏꢐꢀꢍ5ꢅꢎ 6'ꢉꢉꢉꢉꢈꢍ5ꢅꢎꢌ)ꢑ 6'ꢉꢉꢉꢉꢏꢃꢍ5ꢅꢎꢌ)ꢃ 6'ꢉꢉꢉꢉꢏꢅꢒꢍ5ꢅꢎꢌ)ꢅꢀ 6'ꢉꢉꢉꢉꢏꢀꢑꢍ5ꢅꢎꢌ)ꢅꢒ 68%,ꢉꢉꢉ5ꢅꢌ5ꢅꢌLꢑꢈ %1(=ꢉꢉ5ꢅꢌ/223 6'ꢉꢉꢉꢉꢏꢐꢀꢍ5ꢅꢎꢌ)ꢀꢈ LQVWUXFWLRQꢉLVVXHꢉIRUꢉ7RPDVXOR" $'''ꢉ)ꢑꢌ)ꢈꢌ)ꢀ $'''ꢉ)ꢃꢌ)ꢒꢌ)ꢀ $'''ꢉ)ꢅꢀꢌ)ꢅꢈꢌ)ꢀ $'''ꢉ)ꢅꢒꢌ)ꢅꢑꢌ)ꢀ $'''ꢉ)ꢀꢈꢌ)ꢅꢃꢌ)ꢀ ² $VVXPHꢉꢅꢉLQWHJHUꢉꢔꢉꢅꢉIORDWLQJꢉSRLQW ² ꢅꢉ7RPDVXOR FRQWUROꢉIRUꢉLQWHJHUꢌꢉꢅꢉIRUꢉIORDWLQJꢉSRLQW ‡ ,VVXHꢉꢀ;ꢉ&ORFNꢉ5DWHꢌꢉVRꢉWKDWꢉLVVXHꢉUHPDLQVꢉLQꢉRUGHU ‡ 2QO\ꢉ)3ꢉORDGVꢉPLJKWꢉFDXVHꢉGHSHQGHQF\ꢉEHWZHHQꢉ LQWHJHUꢉDQGꢉ)3ꢉLVVXHꢊ ² 5HSODFHꢉORDGꢉUHVHUYDWLRQꢉVWDWLRQꢉZLWKꢉDꢉORDGꢉTXHXHꢓꢉ RSHUDQGVꢉPXVWꢉEHꢉUHDGꢉLQꢉWKHꢉRUGHUꢉWKH\ꢉDUHꢉIHWFKHG ꢅꢈ ꢅꢅ ꢅꢀ ² /RDGꢉFKHFNVꢉDGGUHVVHVꢉLQꢉ6WRUHꢉ4XHXHꢉWRꢉDYRLGꢉ5$:ꢉYLRODWLRQ ² 6WRUHꢉFKHFNVꢉDGGUHVVHVꢉLQꢉ/RDGꢉ4XHXHꢉWRꢉDYRLGꢉ:$5ꢌ:$: ² &DOOHGꢉ´GHFRXSOHGꢉDUFKLWHFWXUHµꢊꢉFRPSDUHꢉZLWKꢉ6PLWKꢉSDSHU ‡ 8QUROOHGꢉꢁꢉWLPHVꢉWRꢉDYRLGꢉGHOD\VꢉꢍꢔꢅꢉGXHꢉWRꢉ66ꢎ ‡ ꢅꢀꢉFORFNVꢌꢉRUꢉꢀꢄꢑꢉFORFNVꢉSHUꢉLWHUDWLRQꢉꢍꢅꢄꢁ;ꢎ &6ꢀꢁꢀꢂ.XELDWRZLF] /HF ꢃꢄꢆ &6ꢀꢁꢀꢂ.XELDWRZLF] /HF ꢃꢄꢅꢈ <ul style="display: flex;"><li style="flex:1">ꢆꢂꢀꢇꢂꢈꢈ </li><li style="flex:1">ꢆꢂꢀꢇꢂꢈꢈ </li></ul>0XOWLSOHꢉ,VVXHꢉ&KDOOHQJHV 9/,:ꢊꢉ9HU\ꢉ/DUJHꢉ,QVWUXFWLRQꢉ:RUG ‡ :KLOHꢉ,QWHJHUꢂ)3ꢉVSOLWꢉLVꢉVLPSOHꢉIRUꢉWKHꢉ+:ꢌꢉJHWꢉ&3,ꢉ RIꢉꢈꢄꢁꢉRQO\ꢉIRUꢉSURJUDPVꢉZLWKꢊ ² ([DFWO\ꢉꢁꢈOꢉ)3ꢉRSHUDWLRQV ‡ (DFKꢉ´LQVWUXFWLRQµꢉKDVꢉH[SOLFLWꢉFRGLQJꢉIRUꢉPXOWLSOHꢉ RSHUDWLRQV ² 1RꢉKD]DUGV ‡ ,IꢉPRUHꢉLQVWUXFWLRQVꢉLVVXHꢉDWꢉVDPHꢉWLPHꢌꢉJUHDWHUꢉ ² ,Qꢉ(3,&ꢌꢉJURXSLQJꢉFDOOHGꢉDꢉ´SDFNHWµ GLIILFXOW\ꢉRIꢉGHFRGHꢉDQGꢉLVVXHꢊ ² ,Qꢉ7UDQVPHWDꢌꢉJURXSLQJꢉFDOOHGꢉDꢉ´PROHFXOHµꢉꢍZLWKꢉ´DWRPVµꢉDVꢉRSVꢎ ² (YHQꢉꢀꢏVFDODUꢉ !ꢉH[DPLQHꢉꢀꢉRSFRGHVꢌꢉꢒꢉUHJLVWHUꢉVSHFLILHUVꢌꢉIꢉGHFLGHꢉ ‡ 7UDGHRIIꢉLQVWUXFWLRQꢉVSDFHꢉIRUꢉVLPSOHꢉGHFRGLQJ LIꢉꢅꢉRUꢉꢀꢉLQVWUXFWLRQVꢉFDQꢉLVVXH <ul style="display: flex;"><li style="flex:1">² 7KHꢉORQJꢉLQVWUXFWLRQꢉZRUGꢉKDVꢉURRPꢉIRUꢉPDQ\ꢉRSHUDWLRQV </li><li style="flex:1">² 5HJLVWHUꢉILOHꢊꢉQHHGꢉꢀ[ꢉUHDGVꢉDQGꢉꢅ[ꢉZULWHVꢂF\FOH </li></ul>² 5HQDPHꢉORJLFꢊꢉPXVWꢉEHꢉDEOHꢉWRꢉUHQDPHꢉVDPHꢉUHJLVWHUꢉPXOWLSOHꢉWLPHVꢉ ² %\ꢉGHILQLWLRQꢌꢉDOOꢉWKHꢉRSHUDWLRQVꢉWKHꢉFRPSLOHUꢉSXWVꢉLQꢉWKHꢉORQJꢉ LQꢉRQHꢉF\FOHRꢉꢉ)RUꢉLQVWDQFHꢌꢉFRQVLGHUꢉꢑꢏZD\ꢉLVVXHꢊ LQVWUXFWLRQꢉZRUGꢉDUHꢉLQGHSHQGHQWꢉ !ꢉH[HFXWHꢉLQꢉSDUDOOHO add r1, r2, r3 sub r4, r1, r2 lw r1, 4(r4) add r5, r1, r2 add p11, p4, p7 sub p22, p11, p4 lw p23, 4(p22) add p12, p23, p4 ² (ꢄJꢄꢌꢉꢀꢉLQWHJHUꢉRSHUDWLRQVꢌꢉꢀꢉ)3ꢉRSVꢌꢉꢀꢉ0HPRU\ꢉUHIVꢌꢉꢅꢉEUDQFK ⇒ª ꢅꢒꢉWRꢉꢀꢑꢉELWVꢉSHUꢉILHOGꢉ !ꢉꢇꢕꢅꢒꢉRUꢉꢅꢅꢀꢉELWVꢉWRꢉꢇꢕꢀꢑꢉRUꢉꢅꢒꢃꢉ ELWVꢉZLGH ² 1HHGꢉFRPSLOLQJꢉWHFKQLTXHꢉWKDWꢉVFKHGXOHVꢉDFURVVꢉVHYHUDOꢉEUDQFKHV ,PDJLQHꢉGRLQJꢉWKLVꢉWUDQVIRUPDWLRQꢉLQꢉDꢉVLQJOHꢉF\FOHR ² 5HVXOWꢉEXVHVꢊꢉ1HHGꢉWRꢉFRPSOHWHꢉPXOWLSOHꢉLQVWUXFWLRQVꢂF\FOH ª 6RꢌꢉQHHGꢉPXOWLSOHꢉEXVHVꢉZLWKꢉDVVRFLDWHGꢉPDWFKLQJꢉORJLFꢉDWꢉHYHU\ꢉ UHVHUYDWLRQꢉVWDWLRQꢄ ª 2UꢌꢉQHHGꢉPXOWLSOHꢉIRUZDUGLQJꢉSDWKV &6ꢀꢁꢀꢂ.XELDWRZLF] /HF ꢃꢄꢅꢅ &6ꢀꢁꢀꢂ.XELDWRZLF] /HF ꢃꢄꢅꢀ <ul style="display: flex;"><li style="flex:1">ꢆꢂꢀꢇꢂꢈꢈ </li><li style="flex:1">ꢆꢂꢀꢇꢂꢈꢈ </li></ul>5HFDOOꢊꢉ8QUROOHGꢉ/RRSꢉWKDWꢉ 0LQLPL]HVꢉ6WDOOVꢉIRUꢉ6FDODU /RRSꢉ8QUROOLQJꢉLQꢉ9/,: <ul style="display: flex;"><li style="flex:1">Memory </li><li style="flex:1">Memory </li><li style="flex:1">FP </li><li style="flex:1">FP </li></ul>op. 2 Int. op/ branch Clock reference 1 reference 2 operation 1 1 Loop: LD F0,0(R1) LD to ADDD: 1 Cycle ADDD to SD: 2 Cycles 234LD LD LD F6,-8(R1) F10,-16(R1) F14,-24(R1) <ul style="display: flex;"><li style="flex:1">LD F0,0(R1) LD F6,-8(R1) </li><li style="flex:1">1</li></ul>234567 LD F10,-16(R1) LD F14,-24(R1) <ul style="display: flex;"><li style="flex:1">LD F18,-32(R1) LD F22,-40(R1) ADDD F4,F0,F2 </li><li style="flex:1">ADDD F8,F6,F2 </li></ul>5678ADDD F4,F0,F2 ADDD F8,F6,F2 ADDD F12,F10,F2 ADDD F16,F14,F2 <ul style="display: flex;"><li style="flex:1">LD F26,-48(R1) </li><li style="flex:1">ADDD F12,F10,F2 ADDD F16,F14,F2 </li></ul>ADDD F20,F18,F2 ADDD F24,F22,F2 <ul style="display: flex;"><li style="flex:1">SD 0(R1),F4 </li><li style="flex:1">SD -8(R1),F8 ADDD F28,F26,F2 </li></ul>SD -16(R1),F12 SD -24(R1),F16 SD -32(R1),F20 SD -40(R1),F24 SD -0(R1),F28 9SD SD SD 0(R1),F4 -8(R1),F8 -16(R1),F12 SUBI R1,R1,#48 BNEZ R1,LOOP 8910 11 12 13 14 SUBI R1,R1,#32 BNEZ R1,LOOP SD Unrolled 7 times to avoid delays 7 results in 9 clocks, or 1.3 clocks per iteration (1.8X) Average: 2.5 ops per clock, 50% efficiency 8(R1),F16 ; 8-32 = -24 14 clock cycles, or 3.5 per iteration Note: Need more registers in VLIW (15 vs. 6 in SS) ꢆꢂꢀꢇꢂꢈꢈ &6ꢀꢁꢀꢂ.XELDWRZLF] /HF ꢃꢄꢅꢐ &6ꢀꢁꢀꢂ.XELDWRZLF] /HF ꢃꢄꢅꢑ ꢆꢂꢀꢇꢂꢈꢈ 5HFDOOꢊꢉ6RIWZDUHꢉ3LSHOLQLQJꢉ([DPSOH 5HFDOOꢊꢉ6RIWZDUHꢉ3LSHOLQLQJ ‡ 2EVHUYDWLRQꢊꢉLIꢉLWHUDWLRQVꢉIURPꢉORRSVꢉDUHꢉLQGHSHQGHQWꢌꢉ WKHQꢉFDQꢉJHWꢉPRUHꢉ,/3ꢉE\ꢉWDNLQJꢉLQVWUXFWLRQVꢉIURPꢉ GLIIHUHQW LWHUDWLRQV ‡ 6RIWZDUHꢉSLSHOLQLQJꢊꢉUHRUJDQL]HVꢉORRSVꢉVRꢉWKDWꢉHDFKꢉ LWHUDWLRQꢉLVꢉPDGHꢉIURPꢉLQVWUXFWLRQVꢉFKRVHQꢉIURPꢉ GLIIHUHQWꢉLWHUDWLRQVꢉRIꢉWKHꢉRULJLQDOꢉORRSꢉꢍ ꢉ7RPDVXOR LQꢉ %HIRUHꢊꢉ8QUROOHGꢉꢐꢉWLPHV After: Software Pipelined ꢅꢉ LD F0,0(R1) 1 SD 0(R1),F4 ; Stores M[i] ꢀ ADDD F4,F0,F2 2 ADDD F4,F0,F2 ; Adds to M[i-1] ꢐ SD 0(R1),F4 F6,-8(R1) <ul style="display: flex;"><li style="flex:1">3 LD </li><li style="flex:1">F0,-16(R1);Loads M[i-2] </li></ul>ꢑ LD 4 SUBI R1,R1,#8 5 BNEZ R1,LOOP ꢁ ADDD F8,F6,F2 ꢒ SD ꢇ LD -8(R1),F8 F10,-16(R1) SW Pipeline ꢃ ADDD F12,F10,F2 6:ꢎ Iteration ꢆ SD -16(R1),F12 0 Iteration 1ꢅꢈ SUBI R1,R1,#24 Iteration <ul style="display: flex;"><li style="flex:1">2</li><li style="flex:1">Iteration </li></ul>3Time ꢅꢅ BNEZ R1,LOOP Iteration 4Loop Unrolled • Symbolic Loop Unrolling – Maximize result-use distance – Less code space than unrolling – Fill & drain pipe only once per loop Softwarepipelined iteration Time vs. once per each unrolled iteration in loop unrolling &6ꢀꢁꢀꢂ.XELDWRZLF] /HF ꢃꢄꢅꢁ &6ꢀꢁꢀꢂ.XELDWRZLF] /HF ꢃꢄꢅꢒ <ul style="display: flex;"><li style="flex:1">ꢆꢂꢀꢇꢂꢈꢈ </li><li style="flex:1">ꢆꢂꢀꢇꢂꢈꢈ </li></ul>6RIWZDUHꢉ3LSHOLQLQJꢉZLWK /RRSꢉ8QUROOLQJꢉLQꢉ9/,: 7UDFHꢉ6FKHGXOLQJ ‡ 3DUDOOHOLVPꢉDFURVVꢉ,)ꢉEUDQFKHVꢉYVꢄꢉ/223ꢉEUDQFKHV ‡ 7ZRꢉVWHSVꢊ Memory reference 1 <ul style="display: flex;"><li style="flex:1">Memory </li><li style="flex:1">FP </li><li style="flex:1">FP </li><li style="flex:1">Int. op/ </li><li style="flex:1">Clock </li></ul><ul style="display: flex;"><li style="flex:1">reference 2 </li><li style="flex:1">operation 1 </li><li style="flex:1">op. 2 branch </li></ul>² 7UDFHꢁ6HOHFWLRQ LD F0,-48(R1) LD F6,-56(R1) LD F10,-40(R1) ST 0(R1),F4 ST -8(R1),F8 ST 8(R1),F12 ADDD F4,F0,F2 ADDD F8,F6,F2 ADDD F12,F10,F2 1

Review Memory Disambiguation Review Explicit Register Renaming

Details

Download

Copyright

We respect the copyrights and intellectual property rights of all users. All uploaded documents are either original works of the uploader or authorized works of the rightful owners.

Support