P2 Tricks, Traps & Differences between P1 (Reference Material Only)
Cluso99
Posts: 18,069
Please keep this thread as a reference 
Any corrections, additions and discussions can be done in the thread linked here...
forums.parallax.com/discussion/167812/p2-tricks-traps-differences-between-p1-discussion/p1?new=1
Update 2022-06-03: ROM code and docs (hard to find, so added links here)
ROM Code Listing (Rev 1 & 2)
forums.parallax.com/discussion/comment/1480216/#Comment_1480216
SD Boot Code (Rev 2)
forums.parallax.com/discussion/170637/p2-sd-boot-code-rev-2-silicon
Monitor/Debugger (Rev2)
forums.parallax.com/discussion/170638/p2-rom-monitor-debugger-rev-1-rev-2-silicon
Any corrections, additions and discussions can be done in the thread linked here...
forums.parallax.com/discussion/167812/p2-tricks-traps-differences-between-p1-discussion/p1?new=1
Update 2022-06-03: ROM code and docs (hard to find, so added links here)
ROM Code Listing (Rev 1 & 2)
forums.parallax.com/discussion/comment/1480216/#Comment_1480216
SD Boot Code (Rev 2)
forums.parallax.com/discussion/170637/p2-sd-boot-code-rev-2-silicon
Monitor/Debugger (Rev2)
forums.parallax.com/discussion/170638/p2-rom-monitor-debugger-rev-1-rev-2-silicon
Comments
P1: Z C P2: Z C '------------------------------------------------------------------------------------------------------------------------------------------ xxx d,PAR xxx d,PTRA ***** needs to be set by SETQ before COGINIT {wc,wz/wz,wc} {wcz} ***** {nr} ***** no equivalent NOP d,s {wc,wz} --- --- ***** no real equivalent AND d,s {wc,wz} R=0 P AND d,s {wc,wz} R=0 P ANDN d,s {wc,wz} R=0 P ANDN d,s {wc,wz} R=0 P OR d,s {wc,wz} R=0 P OR d,s {wc,wz} R=0 P XOR d,s {wc,wz} R=0 P XOR d,s {wc,wz} R=0 P MUXC d,s {wc,wz} R=0 P MUXC d,s {wc,wz} R=0 P MUXNC d,s {wc,wz} R=0 P MUXNC d,s {wc,wz} R=0 P MUXNZ d,s {wc,wz} R=0 P MUXNZ d,s {wc,wz} R=0 P MUXZ d,s {wc,wz} R=0 P MUXZ d,s {wc,wz} R=0 P TEST d,s {wc,wz} R=0 P TEST d,s {wc,wz} R=0 P TESTN d,s {wc,wz} R=0 P TESTN d,s {wc,wz} R=0 P ABS d,s {wc,wz} R=0 S31 ABS d,s {wc,wz} R=0 S31 NEG d,s {wc,wz} R=0 S31 NEG d,s {wc,wz} R=0 R31* ABSNEG d,s {wc,wz} R=0 S31 // ABS d,s {wc} S31 \\ NEG s {wz} R=0 NEGC d,s {wc,wz} R=0 S31 NEGC d,s {wc,wz} R=0 R31* ***** NEGNC d,s {wc,wz} R=0 S31 NEGNC d,s {wc,wz} R=0 R31* ***** NEGNZ d,s {wc,wz} R=0 S31 NEGNZ d,s {wc,wz} R=0 R31* ***** NEGZ d,s {wc,wz} R=0 S31 NEGZ d,s {wc,wz} R=0 R31* ***** NOT d,s {wc,wz} R=0 R31* MOV d,s {wc,wz} R=0 S31 MOV d,s {wc,wz} R=0 S31 ROL d,s {wc,wz} R=0 D31 ROL d,s {wc,wz} R=0 C = last bit shifted out if S[4:0] > 0, else D[31] RCL d,s {wc,wz} R=0 D31 RCL d,s {wc,wz} R=0 C = last bit shifted out if S[4:0] > 0, else D[31] SHL d,s {wc,wz} R=0 D31 SHL d,s {wc,wz} R=0 C = last bit shifted out if S[4:0] > 0, else D[31] d,s {wc,wz} SAL d,s {wc,wz} R=0 C = last bit shifted out if S[4:0] > 0, else D[31] ROR d,s {wc,wz} R=0 D0 ROR d,s {wc,wz} R=0 C = last bit shifted out if S[4:0] > 0, else D[0] RCR d,s {wc,wz} R=0 D0 RCR d,s {wc,wz} R=0 C = last bit shifted out if S[4:0] > 0, else D[0] SHR d,s {wc,wz} R=0 D0 SHR d,s {wc,wz} R=0 C = last bit shifted out if S[4:0] > 0, else D[0] SAR d,s {wc,wz} R=0 D0 SAR d,s {wc,wz} R=0 C = last bit shifted out if S[4:0] > 0, else D[0] REV d,s {wc,wz} R=0 D0 // REV d,s {wc,wz} R=0 C = last bit shifted out if S[4:0] > 0, else D[0] ????? \\ ZEROX ????? ADD d,s {wc,wz} R=0 C ADD d,s {wc,wz} R=0 C SUB d,s {wc,wz} R=0 D<S SUB d,s {wc,wz} R=0 D<S CMP d,s {wc,wz} D=S D<S CMP d,s {wc,wz} D=S D<S SUBR d,s {wc,wz} R=0 D>S CMPR d,s {wc,wz} D=S D>S CMPSUB d,s {wc,wz} D=S D=>S CMPSUB d,s {wc,wz} D=S D=>S *** ADDABS: if S -ve: C=!UB(D-S) SUBABS: if S -ve: C=!UC(D+S) ADDABS d,s {wc,wz} R=0 UC*** ***** SUBABS d,s {wc,wz} R=0 UB*** ***** ADDS d,s {wc,wz} R=0 SO ADDS d,s {wc,wz} R=0 SO ????? SUBS d,s {wc,wz} R=0 SO SUBS d,s {wc,wz} R=0 SO ????? CMPS d,s {wc,wz} D=S D<S CMPS d,s {wc,wz} D=S D<S ????? ADDX d,s {wc,wz} Z&(D+S+C=0) UC ADDX d,s {wc,wz} Z&(D+S+C=0) UC ????? SUBX d,s {wc,wz} R=0 UB SUBX d,s {wc,wz} R=0 UB ????? CMPX d,s {wc,wz} Z&(D=S+C) U(D<S+C) CMPX d,s {wc,wz} Z&(D=S+C) U(D<S+C) ????? ADDSX d,s {wc,wz} Z&(D+S+C=0) SO ADDSX d,s {wc,wz} Z&(D+S+C=0) R31* ????? SUBSX d,s {wc,wz} R=0 SO SUBSX d,s {wc,wz} R=0 R31* ????? CMPSX d,s {wc,wz} Z&(D=S+C) S(D<S+C) CMPSX d,s {wc,wz} Z&(D=S+C) S(D<S+C) ????? SUMC d,s {wc,wz} R=0 SO SUMC d,s {wc,wz} R=0 R31* ????? SUMNC d,s {wc,wz} R=0 SO SUMNC d,s {wc,wz} R=0 R31* ????? SUMNZ d,s {wc,wz} R=0 SO SUMNZ d,s {wc,wz} R=0 R31* ????? SUMZ d,s {wc,wz} R=0 SO SUMZ d,s {wc,wz} R=0 R31* ????? MAX d,s {wc,wz} S=0 D<S FLE d,s {wc,wz} S=0 D<S MAXS d,s {wc,wz} S=0 D<S FLES d,s {wc,wz} S=0 D<S MIN d,s {wc,wz} S=0 D<S FGE d,s {wc,wz} S=0 D<S MINS d,s {wc,wz} S=0 D<S FGES d,s {wc,wz} S=0 D<S MOVS d,s {wc,wz} R=0 --- SETS d,s --- --- ***** \ 2 instruction pipeline MOVD d,s {wc,wz} R=0 --- SETD d,s --- --- ***** | MOVI d,s {wc,wz} R=0 --- SETR d,s --- --- ***** sets iiiiiii-cz / JMPRET d,s {wc,wz} R=0 --- ????? CALL s {wc,wz} R=0 --- ????? JMP s {wc,wz} R=0 --- ????? RET s {wc,wz} R=0 --- ????? DJNZ d,s {wc,wz} R=0 UB DJNZ d,s ***** TJNZ d,s {wc,wz} R=0 0 TJNZ d,s ***** TJZ d,s {wc,wz} R=0 0 TJZ d,s ***** HUBOP s {wc,wz} ??? ??? HUBOP d ????? CLKSET s {wc,wz} --- --- ????? // SETQ d ***** D-->PTRA COGINIT s {wc,wz} ID=0 no-free \\ COGINIT d,s {wc} --- no-free ***** S-->PC COGSTOP s {wc,wz} ID=0 no-free COGSTOP d --- --- ***** COGID s {wc,wz} ID=0 0 COGID d --- --- ***** this cog COGID d {wc} --- running ***** running? LOCKNEW s {wc,wz} ID=0 no-free LOCKNEW d {wc} --- no-free ***** LOCKRET s {wc,wz} ID=0 no-free LOCKRET d --- --- ***** LOCKSET s {wc,wz} ID=0 prev LOCKTRY d {wc} --- obtained ***** C is reversed to P1 LOCKCLR s {wc,wz} ID=0 prev LOCKREL d {wc} --- prev ***** WAITCNT d,s {wc,wz} R=0 UC WAITX d ***** {wc,wz}=d+rnd? WAITPEQ d,s {wc,wz} --- --- // SETPAT d,s ***** D=mask,S=value Z=!D ??? WAITPNE d,s {wc,wz} --- --- \\ WAITPAT {wc,wz} ***** {wc,wz}??? WAITVID d,s {wc,wz} D+S=0 UO ***** RDBYTE d,s {wc,wz} R=0 --- RDBYTE d,s/p {wc,wz} R=0 R7* ***** RDWORD d,s {wc,wz} R=0 --- RDWORD d,s/p {wc,wz} R=0 R15* ***** RDLONG d,s {wc,wz} R=0 --- RDLONG d,s/p {wc,wz} R=0 R31* ***** SETQ for block xfer WRBYTE d,s {wc,wz} --- --- WRBYTE d,s/p --- --- ***** WRWORD d,s {wc,wz} --- --- WRWORD d,s/p --- --- ***** WRLONG d,s {wc,wz} --- --- WRLONG d,s/p --- --- ***** SETQ for block xfer '------------------------------------------------------------------------------------------------------------------------------------------ COG Register Layout: $000..$1EF RAM general-use code/data registers $1F0 PAR RAM / IJMP3 interrupt call address for INT3 $1F1 CNT RAM / IRET3 interrupt return address for INT3 $1F2 INA RAM / IJMP2 interrupt call address for INT2 $1F3 INB RAM / IRET2 interrupt return address for INT2 $1F4 OUTA RAM / IJMP1 interrupt call address for INT1 $1F5 OUTB RAM / IRET1 interrupt return address for INT1 $1F6 DIRA RAM / PA CALLD-imm return, CALLPA parameter, or LOC address $1F7 DIRB RAM / PB CALLD-imm return, CALLPB parameter, or LOC address $1F8 CTRA PTRA pointer A to hub RAM $1F9 CTRB PTRB pointer B to hub RAM $1FA FRQA DIRA output enables for P31..P0 $1FB FRQB DIRB output enables for P63..P32 $1FC PHSA OUTA output states for P31..P0 $1FD PHSB OUTB output states for P63..P32 $1FE VCFG INA * input states for P31..P0 * also debug interrupt call address $1FF VSCL INB ** input states for P63..P32 ** also debug interrupt return address '------------------------------------------------------------------------------------------------------------------------------------------In P1...
LOCKSET D WC returns C=previous lock setting ie C=1=previously set
In P2
LOCKTRY D WC returns C=1=obtained lock Note the reversed result
This is opposite to P1, and also differs from
LOCKNEW D WC returns C=1=no lock available
Here is the definitive example from Chip
https://forums.parallax.com/discussion/comment/1438380/#Comment_1438380
Here is a solution to skipping instructions without using condition codes...
case1 mov cmdtype, #1 ' returns w /CS=0(enabled) jmp #cmdxx case2 mov cmdtype, #0 ' returns w /CS=1(disabled) cmdxx outl #sd_cs '/ /CS=0(enabled) ..... skip cmdtype '| skips next instr if #1 outh #sd_cs '/ /CS=1(disable) if reqdAcknowledgement to PeterJI noticed this very smart coding trick Chip used in checking for a hex character (0..9, A..F, a..f).
Code and table must be in cog.
I also found a shorter way to convert it to a binary nibble.
hexchrs long %00000000_00000000_00000000_00000000 long %00000011_11111111_00000000_00000000 '"0".."9" long %00000000_00000000_00000000_01111110 '"A".."F" long %00000000_00000000_00000000_01111110 '"a".."f" long %00000000_00000000_00000000_00000000 long %00000000_00000000_00000000_00000000 long %00000000_00000000_00000000_00000000 long %00000000_00000000_00000000_00000000 .check altb x,#hexchrs 'check for hex testb 0,x wc if_nc ret 'if not hex, c=0 testbn x,#6 wz 'hex, "0".."9"? if_nz add x,#9 '..make low nibble $A..$F _ret_ and x,#$F 'extract low nibble, return c=1The add x,#9 converts "A..F" to "J..O" and "a..f" to "j..o". "J" is ascii $4A and "j" is ascii $6A.Then we strip off the upper nibble from both the "0..9" and "J..O"/"j..o" leaving $00..$0F"
While it's shorter code to first check for ASCII $80 and above, rather than using the 8 long table we could use a 4 long table. This would save 2 longs.
However, Chip is looking for the fastest code.
The P1 ignores lowest hub address bit(s) for non-aligned hub reads and writes.
The P2 correctly accesses non-aligned word and long reads and writes.
In the P1, there were tricks associated with the lower hub address bit(s) being ignored. This code will fail on P2.
In P1 we did this...
mov count, #(96*2) mov delay, cnt add delay, delay5us :loop waitcnt delay, delay5us 'do something djnz count, #:loopIn P2 we do this...
mov count, #(96*2) getct delay .loop addct1 delay, delay5us waitct1 'do something djnz count, #.loopAnd here is the trap: Our P1 code incorrectly converted to P2
mov count, #(96*2) getct delay addct1 delay, delay5us .loop waitct1 'do something djnz count, #.loopNote we need to include the addct1 instruction into the loop because waitcnt no longer adds to the countWAITX D/#
An alternative to just wait n+2 clocks is the WAITX instruction.
Propeller P2X8C4M46P Instructions v32i Sep2018 Cond Opcode CZ I Dest Source Instr00 01 10 11 Operand(s) Flags -------------------------------------------------------------------------------------------------------------------------------------------------- EEEE 00000ff CZ I DDDDDDDDD SSSSSSSSS ROR ROL SHR SHL D,{#}S {WC/WZ/WCZ} CZ CZ CZ CZ EEEE 00001ff CZ I DDDDDDDDD SSSSSSSSS RCR RCL SAR SAL D,{#}S {WC/WZ/WCZ} CZ CZ CZ CZ EEEE 00010ff CZ I DDDDDDDDD SSSSSSSSS ADD ADDX ADDS ADDSX D,{#}S {WC/WZ/WCZ} CZ CZ CZ CZ EEEE 00011ff CZ I DDDDDDDDD SSSSSSSSS SUB SUBX SUBS SUBSX D,{#}S {WC/WZ/WCZ} CZ CZ CZ CZ EEEE 00100ff CZ I DDDDDDDDD SSSSSSSSS CMP CMPX CMPS CMPSX D,{#}S {WC/WZ/WCZ} CZ CZ CZ CZ EEEE 00101ff CZ I DDDDDDDDD SSSSSSSSS CMPR CMPM SUBR CMPSUB D,{#}S {WC/WZ/WCZ} CZ CZ CZ CZ EEEE 00110ff CZ I DDDDDDDDD SSSSSSSSS FGE FLE FGES FLES D,{#}S {WC/WZ/WCZ} CZ CZ CZ CZ EEEE 00111ff CZ I DDDDDDDDD SSSSSSSSS SUMC SUMNC SUMZ SUMNZ D,{#}S {WC/WZ/WCZ} CZ CZ CZ CZ EEEE 01000ff CZ I DDDDDDDDD SSSSSSSSS TESTB TESTBN TESTB TESTBN D,{#}S WC/WZ;D,{#}S WC/WZ;D,{#}S ANDC/ANDZ;D,{#}S ANDC/ANDZ CZ CZ CZ CZ EEEE 01001ff CZ I DDDDDDDDD SSSSSSSSS TESTB TESTBN TESTB TESTBN D,{#}S ORC/ORZ;D,{#}S ORC/ORZ;D,{#}S XORC/XORZ;D,{#}S XORC/X CZ CZ CZ CZ EEEE 01000ff CZ I DDDDDDDDD SSSSSSSSS BITL BITH BITC BITNC D,{#}S {WCZ} CZ CZ CZ CZ EEEE 01001ff CZ I DDDDDDDDD SSSSSSSSS BITZ BITNZ BITRND BITNOT D,{#}S {WCZ} CZ CZ CZ CZ EEEE 01010ff CZ I DDDDDDDDD SSSSSSSSS AND ANDN OR XOR D,{#}S {WC/WZ/WCZ} CZ CZ CZ CZ EEEE 01011ff CZ I DDDDDDDDD SSSSSSSSS MUXC MUXNC MUXZ MUXNZ D,{#}S {WC/WZ/WCZ} CZ CZ CZ CZ EEEE 01100ff CZ I DDDDDDDDD SSSSSSSSS MOV NOT ABS NEG D,{#}S {WC/WZ/WCZ} CZ CZ CZ CZ EEEE 01101ff CZ I DDDDDDDDD SSSSSSSSS NEGC NEGNC NEGZ NEGNZ D,{#}S {WC/WZ/WCZ} CZ CZ CZ CZ EEEE 01110ff CZ I DDDDDDDDD SSSSSSSSS INCMOD DECMOD ZEROX SIGNX D,{#}S {WC/WZ/WCZ} CZ CZ CZ CZ EEEE 01111ff CZ I DDDDDDDDD SSSSSSSSS ENCOD ONES TEST TESTN D,{#}S {WC/WZ/WCZ} CZ CZ CZ CZ EEEE 1000ffN NN I DDDDDDDDD SSSSSSSSS SETNIB GETNIB ROLNIB D,{#}S,#N -- -- -- EEEE 100011f NN I DDDDDDDDD SSSSSSSSS SETBYTE GETBYTE ROLBYTE D,{#}S,#N -- -- -- EEEE 1001001 fn I DDDDDDDDD SSSSSSSSS SETWORD GETWORD ROLWORD D,{#}S,#N -- -- -- EEEE 1001010 10 I DDDDDDDDD SSSSSSSSS ALTSN ALTGN D,{#}S -- -- EEEE 1001011 ff I DDDDDDDDD SSSSSSSSS ALTSB ALTGB ALTSW ALTGW D,{#}S -- -- -- -- EEEE 1001100 ff I DDDDDDDDD SSSSSSSSS ALTR ALTD ALTS ALTB D,{#}S -- -- -- -- EEEE 1001101 ff I DDDDDDDDD SSSSSSSSS ALTI SETR SETD SETS D,{#}S -- -- -- -- EEEE 1001110 ff I DDDDDDDDD SSSSSSSSS DECOD BMASK CRCBIT CRCNIB D,{#}S -- -- -- -- EEEE 1001111 ff I DDDDDDDDD SSSSSSSSS MUXNITS MUXNIBS MUXQ MOVBYTS D,{#}S -- -- -- -- EEEE 101000f fZ I DDDDDDDDD SSSSSSSSS MUL MULS SCA SCAS D,{#}S {WZ} -Z -Z -Z -Z EEEE 1010010 ff I DDDDDDDDD SSSSSSSSS ADDPIX MULPIX BLNPIX MIXPIX D,{#}S -- -- -- -- EEEE 1010011 ff I DDDDDDDDD SSSSSSSSS ADDCT1 ADDCT2 ADDCT3 WMLONG D,{#}S;D,{#}S;D,{#}S;D,{#}S/P -- -- -- -- EEEE 1010100 Cf I DDDDDDDDD SSSSSSSSS RQPIN RDPIN D,{#}S {WC} C- C- EEEE 1010fff CZ I DDDDDDDDD SSSSSSSSS RDLUT RDBYTE RDWORD RDLONG D,{#}S {WC/WZ/WCZ};D,{#}S/P {WC/WZ/WCZ};D,{#}S/P {WC/WZ/WCZ} CZ CZ CZ CZ EEEE 1011010 fL I DDDDDDDDD SSSSSSSSS CALLPA CALLPB {#}D,{#}S -- -- EEEE 1011011 ff I DDDDDDDDD SSSSSSSSS DJZ DJNZ DJF DJNF D,{#}S -- -- -- -- EEEE 1011100 ff I DDDDDDDDD SSSSSSSSS IJZ IJNZ TJZ TJNZ D,{#}S -- -- -- -- EEEE 1011101 ff I DDDDDDDDD SSSSSSSSS TJF TJNF TJS TJNS D,{#}S -- -- -- -- EEEE 1011110 ff I DDDDDDDDD SSSSSSSSS TJV D,{#}S -- EEEE 1011110 01 I 0000000ff SSSSSSSSS JINT JCT1 JCT2 JCT3 {#}S -- -- -- -- EEEE 1011110 01 I 0000001ff SSSSSSSSS JSE1 JSE2 JSE3 JSE4 {#}S -- -- -- -- EEEE 1011110 01 I 0000010ff SSSSSSSSS JPAT JFBW JXMT JXFI {#}S -- -- -- -- EEEE 1011110 01 I 0000011ff SSSSSSSSS JXRO JXRL JATN JQMT {#}S -- -- -- -- EEEE 1011110 01 I 0000100ff SSSSSSSSS JNINT JNCT1 JNCT2 JNCT3 {#}S -- -- -- -- EEEE 1011110 01 I 0000101ff SSSSSSSSS JNSE1 JNSE2 JNSE3 JNSE4 {#}S -- -- -- -- EEEE 1011110 01 I 0000110ff SSSSSSSSS JNPAT JNFBW JNXMT JNXFI {#}S -- -- -- -- EEEE 1011110 01 I 0000111ff SSSSSSSSS JNXRO JNXRL JNATN JNQMT {#}S -- -- -- -- EEEE 101111f fL I DDDDDDDDD SSSSSSSSS <empty> <empty> SETPAT {#}D,{#}S -- -- -- EEEE 110000f fL I DDDDDDDDD SSSSSSSSS WRPIN WXPIN WYPIN WRLUT {#}D,{#}S -- -- -- -- EEEE 110001f fL I DDDDDDDDD SSSSSSSSS WRBYTE WRWORD WRLONG RDFAST {#}D,{#}S/P;{#}D,{#}S/P;{#}D,{#}S/P;{#}D,{#}S -- -- -- -- EEEE 110010f fL I DDDDDDDDD SSSSSSSSS WRFAST FBLOCK XINIT XZERO {#}D,{#}S -- -- -- -- EEEE 1100110 fL I DDDDDDDDD SSSSSSSSS XCONT REP {#}D,{#}S -- -- EEEE 1100111 CL I DDDDDDDDD SSSSSSSSS COGINIT {#}D,{#}S {WC} C- EEEE 110100f fL I DDDDDDDDD SSSSSSSSS QMUL QDIV QFRAC QSQRT {#}D,{#}S -- -- -- -- EEEE 1101010 fL I DDDDDDDDD SSSSSSSSS QROTATE QVECTOR {#}D,{#}S -- -- EEEE 1101011 00 L DDDDDDDDD 0000000ff HUBSET COGID COGSTOP LOCKNEW {#}D;{#}D {WC};{#}D;D {WC} -- C- -- C- EEEE 1101011 C0 0 DDDDDDDDD 0000001ff LOCKNEW LOCKRET LOCKTRY LOCKREL D {WC};{#}D;{#}D {WC};{#}D {WC} C- -- C- C- EEEE 1101011 CZ 0 DDDDDDDDD 0000100ff RFBYTE RFWORD RFLONG RFVAR D {WC/WZ/WCZ} CZ CZ CZ CZ EEEE 1101011 CZ 0 DDDDDDDDD 0000101ff RFVARS WFBYTE WFWORD WFLONG D {WC/WZ/WCZ};{#}D;{#}D;{#}D CZ -- -- -- EEEE 1101011 CZ 0 DDDDDDDDD 0000110ff GETQX GETQY GETCT GETRND D {WC/WZ/WCZ};D {WC/WZ/WCZ};D;D {WC/WZ/WCZ} CZ CZ -- CZ EEEE 1101011 00 L DDDDDDDDD 0000111ff SETDACS SETXFRQ GETXACC WAITX {#}D;{#}D;D;{#}D {WC/WZ/WCZ} -- -- -- -- EEEE 1101011 00 L DDDDDDDDD 0001000ff SETSE1 SETSE2 SETSE3 SETSE4 {#}D -- -- -- -- EEEE 1101011 CZ 0 0000000ff 000100100 POLLINT POLLCT1 POLLCT2 POLLCT3 {WC/WZ/WCZ} CZ CZ CZ CZ EEEE 1101011 CZ 0 0000001ff 000100100 POLLSE1 POLLSE2 POLLSE3 POLLSE4 {WC/WZ/WCZ} CZ CZ CZ CZ EEEE 1101011 CZ 0 0000010ff 000100100 POLLPAT POLLFBW POLLXMT POLLXFI {WC/WZ/WCZ} CZ CZ CZ CZ EEEE 1101011 CZ 0 0000011ff 000100100 POLLXRO POLLXRL POLLATN POLLQMT {WC/WZ/WCZ} CZ CZ CZ CZ EEEE 1101011 CZ 0 0000100ff 000100100 WAITINT WAITCT1 WAITCT2 WAITCT3 {WC/WZ/WCZ} CZ CZ CZ CZ EEEE 1101011 CZ 0 0000101ff 000100100 WAITSE1 WAITSE2 WAITSE3 WAITSE4 {WC/WZ/WCZ} CZ CZ CZ CZ EEEE 1101011 CZ 0 0000110ff 000100100 WAITPAT WAITFBW WAITXMT WAITXFI {WC/WZ/WCZ} CZ CZ CZ CZ EEEE 1101011 CZ 0 0000111ff 000100100 WAITXRO WAITXRL WAITATN ALLOWI {WC/WZ/WCZ};{WC/WZ/WCZ};{WC/WZ/WCZ}; CZ CZ CZ -- EEEE 1101011 00 0 0001000ff 000100100 ALLOWI STALLI TRGINT1 TRGINT2 -- -- -- -- EEEE 1101011 00 0 0001001ff 000100100 TRGINT3 NIXINT1 NIXINT2 NIXINT3 -- -- -- -- EEEE 1101011 00 L DDDDDDDDD 0001001ff SETINT1 SETINT2 SETINT3 {#}D -- -- -- EEEE 1101011 00 L DDDDDDDDD 0001010ff SETQ SETQ2 PUSH POP {#}D;{#}D;{#}D;D {WC/WZ/WCZ} -- -- -- CZ EEEE 1101011 CZ 0 DDDDDDDDD 0001011ff JMP D {WC/WZ/WCZ} CZ EEEE 1101011 CZ 0 DDDDDDDDD 000101101 CALL RET D {WC/WZ/WCZ};{WC/WZ/WCZ} CZ CZ EEEE 1101011 CZ f DDDDDDDDD 00010111f CALLA RETA CALLB RETB D {WC/WZ/WCZ};{WC/WZ/WCZ};D {WC/WZ/WCZ};{WC/WZ/WCZ} CZ CZ CZ CZ EEEE 1101011 00 L DDDDDDDDD 0001100ff JMPREL SKIP SKIPF EXECF {#}D -- -- -- -- EEEE 1101011 00 0 DDDDDDDDD 0001101ff GETPTR D -- EEEE 1101011 CZ 0 DDDDDDDDD 000110101 GETBRK COGBRK D WC/WZ/WCZ;{#}D CZ -- EEEE 1101011 00 L DDDDDDDDD 000110110 BRK SETLUTS {#}D -- -- EEEE 1101011 00 L DDDDDDDDD 0001110ff SETCY SETCI SETCQ SETCFRQ {#}D -- -- -- -- EEEE 1101011 00 L DDDDDDDDD 0001111ff SETCMOD SETPIV SETPIX COGATN {#}D -- -- -- -- EEEE 1101011 CZ L DDDDDDDDD 0010000ff TESTP TESTPN TESTP TESTPN {#}D WC/WZ;{#}D WC/WZ;{#}D ANDC/ANDZ;{#}D ANDC/ANDZ CZ CZ CZ CZ EEEE 1101011 CZ L DDDDDDDDD 0010001ff TESTP TESTPN TESTP TESTPN {#}D ORC/ORZ;{#}D ORC/ORZ;{#}D XORC/XORZ;{#}D XORC/XORZ CZ CZ CZ CZ EEEE 1101011 CZ L DDDDDDDDD 0010000ff DIRL DIRH DIRC DIRNC {#}D {WCZ} CZ CZ CZ CZ EEEE 1101011 CZ L DDDDDDDDD 0010001ff DIRZ DIRNZ DIRRND DIRNOT {#}D {WCZ} CZ CZ CZ CZ EEEE 1101011 CZ L DDDDDDDDD 0010010ff OUTL OUTH OUTC OUTNC {#}D {WCZ} CZ CZ CZ CZ EEEE 1101011 CZ L DDDDDDDDD 0010011ff OUTZ OUTNZ OUTRND OUTNOT {#}D {WCZ} CZ CZ CZ CZ EEEE 1101011 CZ L DDDDDDDDD 0010100ff FLTL FLTH FLTC FLTNC {#}D {WCZ} CZ CZ CZ CZ EEEE 1101011 CZ L DDDDDDDDD 0010101ff FLTZ FLTNZ FLTRND FLTNOT {#}D {WCZ} CZ CZ CZ CZ EEEE 1101011 CZ L DDDDDDDDD 0010110ff DRVL DRVH DRVC DRVNC {#}D {WCZ} CZ CZ CZ CZ EEEE 1101011 CZ L DDDDDDDDD 0010111ff DRVZ DRVNZ DRVRND DRVNOT {#}D {WCZ} CZ CZ CZ CZ EEEE 1101011 00 0 DDDDDDDDD 0011000ff SPLITB MERGEB SPLITW MERGEW D -- -- -- -- EEEE 1101011 00 0 DDDDDDDDD 0011001ff SEUSSF SEUSSR RGBSQZ RGBEXP D -- -- -- -- EEEE 1101011 00 0 DDDDDDDDD 0011010ff XORO32 REV RCZR RCZL D;D;D {WC/WZ/WCZ};D {WC/WZ/WCZ} -- -- CZ CZ EEEE 1101011 00 0 DDDDDDDDD 0011011ff WRC WRNC WRZ WRNZ D -- -- -- -- EEEE 1101100 RA A AAAAAAAAA AAAAAAAAA JMP CALL CALLA CALLB #A -- -- -- -- EEEE 11100WW RA A AAAAAAAAA AAAAAAAAA CALLD LOC AUGS AUGD PA/PB/PTRA/PTRB,#A;PA/PB/PTRA/PTRB,#A;#N;#N -- -- -- --This should work. Just fill in the values and the values will be calculated for you...
(samples shown for P2-EVAL & P2D2 boards with 150MHz & 148.5MHz selected respectively)
CON '+-------[ Select for P2-EVAL ]------------------------------------------------+ _XTALFREQ = 20_000_000 ' crystal frequency _XDIV = 2 '\ '\ crystal divider to give 10.0MHz _XMUL = 15 '| 150 MHz '| crystal / div * mul to give 150MHz _XDIVP = 1 '/ '/ crystal / div * mul /divp to give 150MHz _XOSC = %10 '15pF ' %00=OFF, %01=OSC, %10=15pF, %11=30pF '+-------[ Select for P2D2 ]---------------------------------------------------+ _XTALFREQ = 12_000_000 ' crystal frequency _XDIV = 4 '\ '\ crystal divider to give 3.0MHz _XMUL = 99 '| 148.5MHz '| crystal / div * mul to give 297.0MHz _XDIVP = 2 '/ '/ crystal / div * mul /divp to give 148.5MHz _XOSC = %01 'OSC ' %00=OFF, %01=OSC, %10=15pF, %11=30pF '+-----------------------------------------------------------------------------+ _XSEL = %11 'XI+PLL ' %00=rcfast(20+MHz), %01=rcslow(~20KHz), %10=XI(5ms), %11=XI+PLL(10ms) _XPPPP = ((_XDIVP>>1) + 15) & $F ' 1->15, 2->0, 4->1, 6->2...30->14 _CLOCKFREQ = _XTALFREQ / _XDIV * _XMUL / _XDIVP ' internal clock frequency _SETFREQ = 1<<24 + (_XDIV-1)<<18 + (_XMUL-1)<<8 + _XPPPP<<4 + _XOSC<<2 ' %0000_000e_dddddd_mmmmmmmmmm_pppp_cc_00 ' setup oscillator _ENAFREQ = _SETFREQ + _XSEL ' %0000_000e_dddddd_mmmmmmmmmm_pppp_cc_ss ' enable oscillator _1us = _clockfreq/1_000_000 ' 1us DAT org 0 '+-------[ Set Xtal ]----------------------------------------------------------+ entry hubset #0 ' set 20MHz+ mode hubset ##_SETFREQ ' setup oscillator waitx ##20_000_000/100 ' ~10ms hubset ##_ENAFREQ ' enable oscillator '+-----------------------------------------------------------------------------+Oops. Fixed this _SETFREQ = 1<<24 +.. was 1<<25Updated: 22 Feb 2019
(Source - https://forums.parallax.com/discussion/comment/1392310/#Comment_1392310)
Cogs share the configuring of each per-pin mode register. A pin will stay configured even if all cogs are restarted. WRPIN {#}D,{#}S Write D to mode register of pin S[5:0], acknowledge smartpin if operating. bit 30 25 20 15 10 5 0 | | | | | | | D/# = %AAAA_BBBB_FFF_PPPPPPPPPPPPP_TT_MMMMM_0 2 1 1 0 5 0 %PPPPPPPPPPPPP: low-level custom pin control common labelling of pin config bits %C = clocked/registered I/O (extra clock for IN and OUT) %I = invert IN output %O = invert OUT input %HHH/LLL = digital out drive strength 000: Fast, 20R 001: 1k5R 010: 15kR 011: 150kR 100: 1mA 101: 100uA 110: 10uA 111: Float PinA is specified pin number PinB is PinA's odd/even pair 0 5 0 %0_VVV_CIOHHHLLL = Digital mode, 3.3 volt DIR enables PinA digital output %VVV = Digital config 000: IN = PinA logic, PinA output from OUT 001: IN = PinA logic, PinA output inverted from IN 010: IN = PinB logic, PinA output inverted from IN 011: IN = PinA schmitt, PinA output from OUT 100: IN = PinA schmitt, PinA output inverted from IN 101: IN = PinB schmitt, PinA output inverted from IN 110: IN = PinA > PinB comparator, PinA output from OUT 111: IN = PinA > PinB comparator, PinA output inverted from IN 0 5 0 %100_VVV_OHHHLLL = ADC_MODE, first order sigma-delta IN has bitstream, sysclock bitrate OUT is PinA digital output, registered DIR enables PinA digital output %VVV = ADC config 000: GIO, 1x (~5 volt range, centred on VIO/2) 001: VIO, 1x " 010: PinB, 1x " (In revC silicon this measures the zero-bias point of the ADC) 011: PinA, 1x " 100: PinA, 3.16x (~1.58 volt range, centred on VIO/2) 101: PinA, 10x (~0.5 volt range, centred on VIO/2) 110: PinA, 31.6x (~0.158 volt range, centred on VIO/2) 111: PinA, 100x (~0.05 volt range, centred on VIO/2) 0 5 0 %101_VV_DDDDDDDD = DAC_MODE (%TT = 00 and %MMMMM = 00000), 8-bit flash, registered OUT enables PinA ADC (ADC config %011), sysclocked bitstream on IN DIR enables PinA DAC output %VV = PinA DAC config 00: 990 ohm, 3.3 volt range 01: 600 ohm, 2.0 volt range 10: 123.75 ohm, 3.3 volt range 11: 75 ohm, 2.0 volt range %DDDDDDDD = DAC level for %TT = %01 and %MMMMM = %00000, %101_VV_xxxxSSSS = COG_DAC mode %SSSS = Cog/streamer select: sets DAC level for %00000 < %MMMMM < %00100 = SMART_DAC mode DIR/IN are usual smartpin ctrl %DDDDDDDD ignored, smartpin sets DAC level for %MMMMM >= %00100 or (%TT = %1x and %MMMMM = %00000) = BIT_DAC mode OUT sets DAC level, (ADC disabled?, IN = ?) 0: 0 = GIO level (revA) 0: %xxxxDDDD (revB) One of sixteen levels 1: %DDDDDDDD (revA) 1: %DDDDxxxx (revB) One of sixteen levels 0 5 0 %11_VV_CDDDDDDDD = COMP_DAC comparator mode, DAC always clocked (registered) DIR enables PinA digital output %VV = Comparator config 00: IN = PinA > D. PinA driven by 1k5R from OUT 01: IN = PinA > D. PinA driven by 1k5R from !IN 10: IN = PinB > D. PinA driven by 1k5R from IN 11: IN = PinB > D. PinA driven by 1k5R from !IN %DDDDDDDD = DAC level for internal analogue compareMode list:
Digital I/O (default)
- inversion
- clocking (registered)
- out strength
- feedback select
- logic in / schmitt in / comparator in
COMP_DAC
- preset level
- pinA/B in select
- feedback select (1500 Ohm out strength)
ADC_MODE
- in/gain select (pinB is disabled in revC silicon)
DAC_MODE
- strength
- preset level
- COG_DAC
- - specify cog
- - cog/streamer provides level
- SMART_DAC
- - associated smartpin provides level
- BIT_DAC
- - preset split level
Updated 20-11-2018 to correct smartpin mode number for capturing ADC bitstream.
25-11-2018: Reverse the update. Doh!
26-12-2018: Typo, R -> % in BIT_DAC mode line. And stated for engineering sample.
26-3-2019: Add link to source "pin_modes.png" sheet.
3-7-2019: Add "0" and "5" bit position indicators for faster constant crafting.
17-11-2019: Add changed revB silicon BIT_DAC mode. Mark DAC_MODE and its sub-modes as registered I/O.
1-12-2019: Add short mode list.
4-4-2020: RevC update.
decod y,#10 'ready to input $400 bytes from SPI' good for..DECOD D,#n ' 1 << n n n 0 -> $1 = %1 16 -> $1_0000 = %1_0000_0000_0000_0000 1 -> $2 = %10 17 -> $2_0000 = %10_0000_0000_0000_0000 2 -> $4 = %100 18 -> $4_0000 = %100_0000_0000_0000_0000 3 -> $8 = %1000 19 -> $8_0000 = %1000_0000_0000_0000_0000 4 -> $10 = %1_0000 20 -> $10_0000 = %1_0000_0000_0000_0000_0000 5 -> $20 = %10_0000 21 -> $20_0000 = %10_0000_0000_0000_0000_0000 6 -> $40 = %100_0000 22 -> $40_0000 = %100_0000_0000_0000_0000_0000 7 -> $80 = %1000_0000 23 -> $80_0000 = %1000_0000_0000_0000_0000_0000 8 -> $100 = %1_0000_0000 24 -> $100_0000 = %1_0000_0000_0000_0000_0000_0000 9 -> $200 = %10_0000_0000 25 -> $200_0000 = %10_0000_0000_0000_0000_0000_0000 10 -> $400 = %100_0000_0000 26 -> $400_0000 = %100_0000_0000_0000_0000_0000_0000 11 -> $800 = %1000_0000_0000 27 -> $800_0000 = %1000_0000_0000_0000_0000_0000_0000 12 -> $1000 = %1_0000_0000_0000 28 -> $1000_0000 = %1_0000_0000_0000_0000_0000_0000_0000 13 -> $2000 = %10_0000_0000_0000 29 -> $2000_0000 = %10_0000_0000_0000_0000_0000_0000_0000 14 -> $4000 = %100_0000_0000_0000 30 -> $4000_0000 = %100_0000_0000_0000_0000_0000_0000_0000 15 -> $8000 = %1000_0000_0000_0000 31 -> $8000_0000 = %1000_0000_0000_0000_0000_0000_0000_0000Also this to load $FFFF_FFFFneg pb,#1 'set command bits to all 1'sUpdated with more info 22 Feb 2019BMASK D,#11 'D = $FFF
BMASK D,#15 'D = $FFFF
BMASK D,#30 'D = $7FFF_FFFF
So here is another way of expressing this...
BMASK D,#n ' where 'n+1' is the number of LSB 1's n n 0 -> $1 = %1 16 -> $1_FFFF = %1_1111_1111_1111_1111 1 -> $3 = %11 17 -> $3_FFFF = %11_1111_1111_1111_1111 2 -> $7 = %111 18 -> $7_FFFF = %111_1111_1111_1111_1111 3 -> $F = %1111 19 -> $F_FFFF = %1111_1111_1111_1111_1111 4 -> $1F = %1_1111 20 -> $1F_FFFF = %1_1111_1111_1111_1111_1111 5 -> $3F = %11_1111 21 -> $3F_FFFF = %11_1111_1111_1111_1111_1111 6 -> $7F = %111_1111 22 -> $7F_FFFF = %111_1111_1111_1111_1111_1111 7 -> $FF = %1111_1111 23 -> $FF_FFFF = %1111_1111_1111_1111_1111_1111 8 -> $1FF = %1_1111_1111 24 -> $1FF_FFFF = %1_1111_1111_1111_1111_1111_1111 9 -> $3FF = %11_1111_1111 25 -> $3FF_FFFF = %11_1111_1111_1111_1111_1111_1111 10 -> $7FF = %111_1111_1111 26 -> $7FF_FFFF = %111_1111_1111_1111_1111_1111_1111 11 -> $FFF = %1111_1111_1111 27 -> $FFF_FFFF = %1111_1111_1111_1111_1111_1111_1111 12 -> $1FFF = %1_1111_1111_1111 28 -> $1FFF_FFFF = %1_1111_1111_1111_1111_1111_1111_1111 13 -> $3FFF = %11_1111_1111_1111 29 -> $3FFF_FFFF = %11_1111_1111_1111_1111_1111_1111_1111 14 -> $7FFF = %111_1111_1111_1111 30 -> $7FFF_FFFF = %111_1111_1111_1111_1111_1111_1111_1111 15 -> $FFFF = %1111_1111_1111_1111 31 -> $FFFF_FFFF = %1111_1111_1111_1111_1111_1111_1111_1111adjusted per Chip's following suggestionHere is a section of code to record 'sample_length' of P0-P31 or P32-P63 using the streamer into HUB RAM at 'samples'...
con ' Streams INA (32 bits) to hub. sample_length = 4000 'longs dat orgh org 0 ... setxfrq ##$8000_0000 'sysclk sample rate wrfast #0,##@samples ' %1111_xxxx_xppp_xxxx << 16 ' 000 P31-0 ' 001 P39-8 ' 010 P47-16 ' 011 P55-24 ' 100 P63-32 ' 101 P7-0+P63-40 ' 110 P15-0+P63-48 ' 111 P23-0+P63-56 xinit ##%1111_0000_0000_0000 << 16 | sample_length,#0 'P00-31 ' xinit ##%1111_0000_0100_0000 << 16 | sample_length,#0 'P32-63 waitxfi '******************************************************************* orgh $4000 samples long 0[sample_length] '*******************************************************************LOC/MOV syntax ORG $00F ORGH $00110 ORGH $00600 from hubexec op-code PA-data op-code PA-data op-code PA-data ============================================================================== loc pa, #label fe80000f 0000000f fe800110 00000110 fe900198 00000600 loc pa, #@label fe80003c 0000003c fe800110 00000110 fe900174 00000600 loc pa, #\label fe80000f 0000000f fe800110 00000110 fe800600 00000600 loc pa, #\@label fe80003c 0000003c fe800110 00000110 fe800600 00000600 mov pa, ##label f607ec0f 0000000f f607ed10 00000110 f607ec00 00000600 mov pa, ##@label f607ec3c 0000003c f607ed10 00000110 f607ec00 00000600 LOC/MOV syntax ORG $00F ORGH $00110 ORGH $00600 from cogexec op-code PA-data op-code PA-data op-code PA-data ============================================================================== loc pa, #label fe9fffe0 000ffff7 fe9003dc 000003f5 fe800600 00000600 loc pa, #@label fe900070 00000090 fe9003b8 000003da fe800600 00000600 loc pa, #\label fe80000f 0000000f fe800110 00000110 fe800600 00000600 loc pa, #\@label fe80003c 0000003c fe800110 00000110 fe800600 00000600 mov pa, ##label f607ec0f 0000000f f607ed10 00000110 f607ec00 00000600 mov pa, ##@label f607ec3c 0000003c f607ed10 00000110 f607ec00 00000600NOTE: When specifying a numerical immediate in place of the label, it is treated as an absolute address and the same rules apply, ie: it will be encoded as PC-relative if possible, as per above. However, "@" produces an error with Pnut but not with p2asm. p2asm will perform a left shift by 2.
Test code added: 2019-4-11
UPDATES:
2019-4-12: Bug is fixed in fastspin v3.9.25 - https://github.com/totalspectrum/spin2cpp
2019-4-13: Bug is fixed in p2asm v0.015 - https://github.com/davehein/p2gcc
2020-7-05: Bug is fixed in Pnut v34 (5 Feb 2020) - http://forums.parallax.com/discussion/comment/1488890/#Comment_1488890
mov lmm_x,#0 testb lmm_x,#0 wz ' nz <<<<< testbn lmm_x,#0 wz ' z <<<<< testb lmm_x,#0 wc ' nc testbn lmm_x,#0 wc ' c and lmm_x,#1 wz ' z mov lmm_x,#1 testb lmm_x,#0 wz ' z <<<<< testbn lmm_x,#0 wz ' nz <<<<< testb lmm_x,#0 wc ' c testbn lmm_x,#0 wc ' nc and lmm_x,#1 wz ' nzFor anyone new reading, all register-level instructions affect the Z flag as you would expect, where it gets set if the result was zero.
For the bit-level instructions, on the other hand, C and Z are both read and written directly, without semantic consideration for what Z usually means.
The known one is the last instruction within the REP block cannot be a branching instruction. If a branching instruction is used then the branch distance will have the block length subtracted from it. It won't be remedied, so just don't do it.
Any intentionally cancelling branches must be at least one instruction back from the end of the REP block.
UPDATE: This flaw only affects relative branching! Absolute immediate and register direct can work as usual with the last instruction of a REP block. Alternatively, a compensation (block length added) applied to the relative branch also works. Further reading - https://forums.parallax.com/discussion/comment/1488366/#Comment_1488366
The until recently unknown one is with the Jxxx branch-on-event instructions. Using any of these instructions anywhere within the REP block will intermittently fail to branch upon event. When the failure occurs, execution will continue out the end of the REP block and even fail to take the first following branch.
This one is expected to be fixed. Example code of accommodating, and alternative below - https://forums.parallax.com/discussion/comment/1458393/#Comment_1458393
UPDATE: This one was fixed with v33 FPGA files, rev B silicon.
Some extra detail - https://forums.parallax.com/discussion/comment/1461458/#Comment_1461458
and https://forums.parallax.com/discussion/169438/rep-blocks-and-branching-issue/p1
' convert nibble to ASCII hex char getnib x,value,#7 '\ either instruction extracts only the lower nibble and x,#$0F '/ or x,#"0" cmp x,#";" wc ' : -> A etc if_nc add x,#7There's a hardware flaw with shared lutRAM. A simultaneous read and write will glitch the read data. The glitch patterns change slightly with each run but the alignment doesn't. Same for different sys clock rates.
v32i FPGA image on P123 board @ 20 MHz
lut glitch test => ffffffff 00000c00 00000000 00000000 alignment = 2 ticks = 14 lut glitch test => 00000000 fbfffffb ffffffff ffffffff alignment = 2 ticks = 14 lut glitch test => aaaaaaaa 51555d51 55555555 55555555 alignment = 2 ticks = 14 lut glitch test => 55555555 aaaaaaaa aaaaaaaa aaaaaaaa alignment = 2 ticks = 14RevA P2ES board @ 20 MHz
lut glitch test => ffffffff 4a41febf 00000000 00000000 alignment = 2 ticks = 14 lut glitch test => 00000000 00000000 ffffffff ffffffff alignment = 2 ticks = 14 lut glitch test => aaaaaaaa 0a80aaaa 55555555 55555555 alignment = 2 ticks = 14 lut glitch test => 55555555 40415415 aaaaaaaa aaaaaaaa alignment = 2 ticks = 14EDIT: Updated with extra tests. Thanks Brian.
EDIT2: Added that revB has this fixed.
You've managed to add a forth comment now!
Seem the forum software does not actually allow that, so I've done the next best thing..... ♪
much harder to spot and can lead you (well me) running around in circles trying to track down very strange behaviours
that seem to defy logic:
cognew (@entry, ...) DAT ORG rogue long 0 entry ' your codeOf course the ORG should be after the random long data, otherwise all the addressing is thrown, butthe effect is to omit the leading instructions in call'ed routines (jmps are relative and tend to work),
which can have subtle and bizarre consequences.
On the P1 all branches get affected and things tend to fall over completely rather than limp along misbehaving
It would be nice to get an assembler warning if the first entry after ORG 0 is not an instruction.
P2 will be a little different to P1 in that you can start the cog at other than address COG $0, and also because we don't really have a NOP opcode.
Postedit
In P1 it was a common trick to use
LONG <somevalue>
where <somevalue> was <= 18-bits
This meant that the conditional bits EEEE=0000 and so the instruction would be treated as a NOP.
In P2 the EEEE=0000 is a valid instruction with the _RET_ condition. The instruction executes, and if not a taken branch it will also perform a RET instruction.
Therefore, any value other than all zeros will execute some intsruction.
Thus
LONG <any-non-zero-value>
will NOT BE TREATED AS A NOP in P2 !!!
0000 0000000 000 000000000 000000000 NOP