Forth Benchmarks
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Forth83 Benchmarks#

Below is a collection of some Benchmarks for Forth83 systems like VolksForth.

I found most of these benchmarks on comp.lang.forth, Hans Bzemers 4th and Marcel Hendrix benchmark collection

Results#

Name System Forth Benchmark Time (sec/round)
Carsten Strotmann Atari Portfolio 8088 4.92Mhz VolksForth MS-DOS (ITC) Integer Calc 4.96
Carsten Strotmann Amstrad NC100 Z80 4.606Mhz VolksForth CP/M (ITC) Integer Calc 6.23
Martin Metz Amstrad NC100 Z80 4.606Mhz VolksForth CP/M (ITC) GCD 1 38.1
Andreas Böhm Commodore C64 6510 Audiogenic Forth-64 Integer Calc 526
Andreas Böhm Commodore C64 6510 Audiogenic Forth-64 Count Bits 140.22
Andreas Böhm Commodore C64 6510 Audiogenic Forth-64 Sieve Bench 18.1
Andreas Böhm Commodore C64 6510 Audiogenic Forth-64 GCD 1 215.52
Andreas Böhm Commodore C64 6510 Audiogenic Forth-64 GCD 2 84.84
H. Jakob c't 86 8086 5Mhz Laxen/Perry F83 Integer Calc 9
Neil Franklin HP 100LX 80186 7.9Mhz VolksForth 3.81.41 MS-DOS Integer Calc 2.8
Carsten Strotmann Atari 130XE 6502 1.79Mhz VolksForth 3.81 Integer Calc 596
Carsten Strotmann Atari 130XE 6502 1.79Mhz noDMA VolksForth 3.81 Integer Calc 438
J. Kunz DEC 3000-600 Alpha 21064 175Mhz pForth Integer Calc 0.091
J. Kunz DEC 3000-600 Alpha 21064 175Mhz pForth Fibonacci 1 0.0038
J. Kunz DEC 3000-600 Alpha 21064 175Mhz pForth Fibonacci 2 0.00001425
J. Kunz DEC 3000-600 Alpha 21064 175Mhz pForth Nesting 32Mil 22
J. Kunz DEC 3000-600 Alpha 21064 175Mhz pForth 6502emu 18
Ingo Soetebier Nextstation 68040 33Mhz pfe Nesting 1Mil 340
KC85 Team KC85/4 U880 4Mhz VolksForth CP/M Nesting 1Mil 144
Venty Thinkpad T61, 2Ghz Core Duo gforth-fast, Linux Integer Calc 0.0013
Venty Thinkpad T61, 2Ghz Core Duo gforth, Linux Integer Calc 0.0019
Venty Nokia N900 ARM A8 600Mhz gforth-fast, Linux Nesting 32Mil 3.9
Venty Nokia N900 ARM A8 600Mhz gforth-fast, Linux Sieve Bench 0.015
Venty Nokia N900 ARM A8 600Mhz gforth-fast, Linux 6502emu 1
Venty Nokia N900 ARM A8 600Mhz gforth-dtc, Linux Nesting 32Mil 5.5
Venty Nokia N900 ARM A8 600Mhz gforth-dtc, Linux Sieve Bench 0.025
Venty Nokia N900 ARM A8 600Mhz gforth-dtc, Linux 6502emu 1.8
Venty Nokia N900 ARM A8 600Mhz gforth-itc, Linux Nesting 32Mil 6.9
Venty Nokia N900 ARM A8 600Mhz gforth-itc, Linux Sieve Bench 0.028
Venty Nokia N900 ARM A8 600Mhz gforth-itc, Linux 6502emu 2.2
Thorsten Kuphaldt Amiga 3000 68030 25Mhz jforth Integer Bench 0.24
Thorsten Kuphaldt Amiga 3000 68030 25Mhz jforth Nesting 1Mil 1.32
Thorsten Kuphaldt Amiga 3000 68030 25Mhz jforth Memory Move 0.67
Thorsten Kuphaldt Amiga 3000 68030 25Mhz jforth Sieve Bench 0.148
Thorsten Kuphaldt Amiga 3000 68030 25Mhz jforth GCD 1 0.64
Stefan Herold Amstrad 6128+ Z80A 4Mhz Uniforth Integer Calc 17
Stefan Herold Amstrad 6128+ Z80A 4Mhz Uniforth Fibonacci 2 0.23
Stefan Herold Amstrad 6128+ Z80A 4Mhz Uniforth Nesting 1Mil 206
Stefan Herold Amstrad 6128+ Z80A 4Mhz Uniforth Sieve Bench 12
Ingo Soetebier iBook PPC 750lx (G3) 600Mhz OpenFirmware Integer Calc 0.03
Ingo Soetebier iBook PPC 750lx (G3) 600Mhz OpenFirmware Fibonacci 1 0.0026
Ingo Soetebier iBook PPC 750lx (G3) 600Mhz OpenFirmware Fibonacci 2 0.0027
Ingo Soetebier iBook PPC 750lx (G3) 600Mhz OpenFirmware Nesting 1Mil 1
Ingo Soetebier iBook PPC 750lx (G3) 600Mhz OpenFirmware Sieve Bench 0.031
Ingo Soetebier iBook PPC 750lx (G3) 600Mhz OpenFirmware GCD 1 0.024
Michael Kalus Rockwell R1200-14, 2Mhz 65F12 RSC-Forth Fibonacci 1 16.09
Michael Kalus Rockwell R1200-14, 2Mhz 65F12 RSC-Forth Fibonacci 2 0.05
Michael Kalus Rockwell R1200-14, 2Mhz 65F12 RSC-Forth Nesting 1Mil 149
Michael Kalus Rockwell R1200-14, 2Mhz 65F12 RSC-Forth Integer Calc 31
Matthias Trute Atmega16 8MHz amForth 4.4 Integer Calc 1.56
Matthias Trute Atmega16 8MHz amForth 4.4 Fibonacci 1 1.46
Matthias Trute Atmega16 8MHz amForth 4.4 Fibonacci 2 0.0047
Matthias Trute Atmega16 8MHz amForth 4.4 Nesting 1Mil 15.4
Matthias Trute Atmega16 8MHz amForth 4.4 Nesting 32Mil 489
Matthias Trute Atmega16 8MHz amForth 4.4 GCD 1 7.12
Matthias Trute Atmega16 8MHz amForth 4.4 GCD 2 10.5
Matthias Trute Atmega16 8MHz amForth 4.4 Takeuchi 0.7
Michael Kalus MSP430FR5739, 8Mhz DCO intern MSP-EXP430FR5739 Experimenter Board CamelForth Integer Calc 100x 02'45':10
Michael Kalus MSP430FR5739, 8Mhz DCO intern MSP-EXP430FR5739 Experimenter Board CamelForth FIB1 100x 00'46':39
Michael Kalus MSP430FR5739, 8Mhz DCO intern MSP-EXP430FR5739 Experimenter Board CamelForth FIB2 10000x 00'16':91
Michael Kalus MSP430FR5739, 8Mhz DCO intern MSP-EXP430FR5739 Experimenter Board CamelForth Nesting 32Mil 02'31':23
Carsten Strotmann IBM L40S (386SX) mina (Fig-Forth) Fib2 (1000) 8s
Carsten Strotmann IBM L40X (386SX) F83 (Laxen & Perry) Fib2 (1000) 8s
Carsten Strotmann IBM L40X (386SX) GNU Forth 0.5.0 ec8086 Fib2 (1000) 24s
Carsten Strotmann IBM L40X (386SX) VolksForth MS-DOS Fibonacci 1 0.36s
Thorsten Schoeler Sinclair Spectrum+ Aber Forth (FIG-Forth) Integer 25s
Thorsten Schoeler " " prime 11s
Thorsten Schoeler " " Nesting 1m 3m17s
Thorsten Schoeler " " GCD1 2m14s
Thorsten Schoeler " " Fib2 (1000) 1m46s
Thorsten Schoeler HX-20 Epson Forth E1.0 Fib2 (1000) 3m16s
Thorsten Schoeler HX-20 " Nesting 32mil 2h43m49s
Thorsten Schoeler HX-20 " Nesting 1mil 5m08s
Thorsten Schoeler HX-20 " Integer 32tsd 1m03s
Thorsten Schoeler HX-20 6301 614khz " Prime 23s
Wolfgang Stief SUN SparcStation 10 TI TMS390255 OpenFirmware Integer 0,14s
Wolfgang Stief SUN SparcStation 10 TI TMS390255 OpenFirmware Fib1 0,005s
Wolfgang Stief SUN SparcStation 10 TI TMS390255 OpenFirmware Fib2 0,2s
Wolfgang Stief SUN SparcStation 10 TI TMS390255 OpenFirmware Memory Move 143s
Wolfgang Stief SUN SparcStation 10 TI TMS390255 OpenFirmware Prime 0,11s
Wolfgang Stief SUN SparcStation 10 TI TMS390255 OpenFirmware GCD1 0,51s
Wolfgang Stief SUN SparcStation 10 TI TMS390255 OpenFirmware GCD2 0,65s
Wolfgang Stief SUN SparcStation 10 TI TMS390255 OpenFirmware Takeuchi 0,06s
Wolfgang Stief SUN Ultra 1 200 Mhz UltraSprac OpenBoot 3.25 Integer 0,33s
Wolfgang Stief SUN Ultra 1 200 Mhz UltraSprac OpenBoot 3.25 Fib1 0,014s
Wolfgang Stief SUN Ultra 1 200 Mhz UltraSprac OpenBoot 3.25 Fib2 0,06s
Wolfgang Stief SUN Ultra 1 200 Mhz UltraSprac OpenBoot 3.25 Nesting 32mil 9s
Wolfgang Stief SUN Ultra 1 200 Mhz UltraSprac OpenBoot 3.25 Mempry Move 0,014s
Wolfgang Stief SUN Ultra 1 200 Mhz UltraSprac OpenBoot 3.25 Prime 0,03s
Wolfgang Stief SUN Ultra 1 200 Mhz UltraSprac OpenBoot 3.25 GCD1 0,08s
Wolfgang Stief SUN Ultra 1 200 Mhz UltraSprac OpenBoot 3.25 GCD2 0,11s
Wolfgang Stief SUN Ultra 1 200 Mhz UltraSprac OpenBoot 3.25 Takeuchi 0,009s
Thorsten Schoeler Fignition (ATMEL) Fignition Forth fib2 (1000) 13s
Stefan Niestegge Atari Falcom 68060 100mhz f68kans Integer 0,022s
Stefan Niestegge Atari Falcon 68060 100mhz f68kans Fib2 0,0012s
Stefan Niestegge Atari Falcon 68060 f68kans Countbits 0,05s
Stefan Niestegge Atari Falcon 68060 f68kans GCD1 0,063s
Stefan Niestegge Atari Falcon 68060 f68kans GCD2 0,067s
Stefan Niestegge Atari Falcon 68060 f68kans Nesting 32mil 7,4s
Thorsten Kuphaldt C64 (normal) Forth64 Nesting 1mill 6m20
" C64 (Turbo FPGA 6502) Forth64 Nesting 1mill 25s
" C64 (normal) Forth64 Fib2 (1000) 3m50s
" C64 (Turbo FPGA 6502) Forth64 Fib2 (1000) 16s
Martin Neitzel Asus EeePC 1000h (Atom N270 1.6Ghz) FreeBSD 9 FICL Bootloader Integer 0,00075s
Martin Neitzel Asus EeePC 1000h (Atom N270 1.6Ghz) FreeBSD 9 FICL Bootloader Fib2 66s
Martin Neitzel Asus EeePC 1000h (Atom N270 1.6Ghz) FreeBSD 9 FICL Bootloader Nesting 1mil 0.66s
Martin Neitzel Asus EeePC 1000h (Atom N270 1.6Ghz) FreeBSD 9 FICL Bootloader Nesting 32mil 21s
Martin Neitzel Asus EeePC 1000h (Atom N270 1.6Ghz) FreeBSD 9 FICL Bootloader GCD2 0.57s
Sabine "Atari Frosch" Engelhardt Atari Portfolio VolksForth 3.81 Fib2 35s
Sabine "Atari Frosch" Engelhardt Atari Portfolio VolksForth 3.81 Prime 6s
Sabine "Atari Frosch" Engelhardt Atari Portfolio VolksForth 3.81 Takeuchi 17s
Herbert Lange Compaq Deskpro P166 pForth V27 Integer Calc 0,052s
Herbert Lange Compaq Deskpro P166 pForth V27 Fib1 0,061s
Herbert Lange Compaq Deskpro P166 pForth V27 Fib2 0,001s
Herbert Lange Compaq Deskpro P166 pForth V27 Nesting 32mil 15,42s
Herbert Lange Compaq Deskpro P166 pForth V27 Memory Move 0,124s
Herbert Lange Compaq Deskpro P166 pForth V27 Prime 0,007s
Herbert Lange Compaq Deskpro P166 pForth V27 GCD1 0,002s
Herbert Lange Apple iMac G3 400Mhz pForth V27 Integer Calc 0,013s
Herbert Lange Apple iMac G3 400Mhz pForth V27 Fib1 0,015s
Herbert Lange Apple iMac G3 400Mhz pForth V27 Fib2 0,001s
Herbert Lange Apple iMac G3 400Mhz pForth V27 Nesting 32mil 4,335s
Herbert Lange Apple iMac G3 400Mhz pForth V27 Memory Move 0,028s
Herbert Lange Apple iMac G3 400Mhz pForth V27 Prime 0,017s
Herbert Lange Apple iMac G3 400Mhz pForth V27 GCD1 0,063s
Herbert Lange DEC 3000 400s pForth V27 Integer 0,123s
Herbert Lange DEC 3000 400s pForth V27 Fib1 0,098s
Herbert Lange DEC 3000 400s pForth V27 Fib21 0,001s
Herbert Lange DEC 3000 400s pForth V27 Nesting 32mil 30,694s
Herbert Lange DEC 3000 400s pForth V27 Memory Move 0,207s
Herbert Lange DEC 3000 400s pForth V27 Prime 0,117s
Herbert Lange DEC 3000 400s pForth V27 GCD1 0,483
Herbert Lange SUN Ultra 1 Creator 3D pForth V27 Integer 0,049s
Herbert Lange SUN Ultra 1 Creator 3D pForth V27 Fib1 0,052s
Herbert Lange SUN Ultra 1 Creator 3D pForth V27 Fib2 0,001s
Herbert Lange SUN Ultra 1 Creator 3D pForth V27 Nesting 32mil 15,631s
Herbert Lange SUN Ultra 1 Creator 3D pForth V27 Memory Move 0,093s
Herbert Lange SUN Ultra 1 Creator 3D pForth V27 Prime 0,060s
Herbert Lange SUN Ultra 1 Creator 3D pForth V27 GCD1 0,022s
Ralf Neumann mc-CP/M Z80 4Mhz FIG-Forth 1.1 Fib2 1m19s
Ralf Neumann Prof80 CP/M Z80 6Mhz FIG-Forth 1.1 Fib2 53s

Benchme Helper#

: benchme ( xt n -- ) \ executes the word with the execution token 'xt' n-times
  dup >r              \ save number of iterations
  0 do dup execute loop \ execute word. word must have a neutral stack effect
  cr r> . ." Iterations." cr \ emit message
;

Integer Calculations #

32000 constant intMax

variable intResult

: DoInt
  1 dup intResult dup >r !
  begin
    dup intMax <
  while
    dup negate r@ +! 1+
    dup r@ +! 1+
    r@ @ over * r@ ! 1+
    r@ @ over / r@ ! 1+
  repeat
  r> drop drop
;

Fibonacci 1#

This version uses a recursive call. Recursive calls are not standardized in early Forth systems. The word to call the current definition can have different names in your forth (recurse, self, ...). Please check you system documentation (if available) or the wordlist (using WORDS or VLIST).

: fib1 ( n1 -- n2 )
    dup 2 < if drop 1 exit then
    dup  1- recursive 
    swap 2- recursive  + ;
    
: fib1-bench 1000 0 do i fib1 drop loop ;

Fibonacci 2#

: fib2 ( n1 -- n2 )                                                                
   0 1 rot 0 ?do 
      over + swap loop 
   drop ;
 
: fib2-bench 1000 0 do i fib2 drop loop ;

Forth Nesting Benchmark#

 \ Forth nesting (NEXT) Benchmark                     cas20101204                   
 : bottom ;                                                                         
 : 1st bottom bottom ;  : 2nd 1st 1st ;      : 3rd 2nd 2nd ;                        
 : 4th 3rd 3rd ;        : 5th 4th 4th ;      : 6th 5th 5th ;                        
 : 7th 6th 6th ;        : 8th 7th 7th ;      : 9th 8th 8th ;                        
 : 10th 9th 9th ;       : 11th 10th 10th ;   : 12th 11th 11th ;                     
 : 13th 12th 12th ;     : 14th 13th 13th ;   : 15th 14th 14th ;                     
 : 16th 15th 15th ;     : 17th 16th 16th ;   : 18th 17th 17th ;                     
 : 19th 18th 18th ;     : 20th 19th 19th ;   : 21th 20th 20th ;                     
 : 22th 21th 21th ;     : 23th 22th 22th ;   : 24th 23th 23th ;                     
 : 25th 24th 24th ;                                                                 
                                                                                    
 : 32million   CR ." 32 million nest/unnest operations" 25th ;                      
 :  1million   CR ."  1 million nest/unnest operations" 20th ;                      
                                                                                    
 CR .( enter 1million or 32million )         

Forth Memory Move Benchmark#

\ Forth Memory Move Benchmark                       cas 20101204                   
  8192 CONSTANT bufsize                                                             
 VARIABLE buf1 HERE bufsize 1+ allot BUF1 !                                         
 VARIABLE buf2 HERE bufsize 1+ allot BUF2 !                                         
                                                                                    
 : test-CMOVE 49 0 DO BUF1 @ BUF2 @ bufsize CMOVE LOOP ;                            
                                                                                    
 : test-CMOVE> 49 0 DO BUF2 @ BUF1 @ bufsize CMOVE> LOOP ;                          
                                                                                    
 : test-MOVE> 49 0 DO BUF1 @ BUF2 @ bufsize MOVE LOOP ;                             
                                                                                    
 : test-<MOVE 49 0 DO BUF2 @ BUF1 @ bufsize MOVE LOOP ;     
 
 : move-bench test-CMOVE test-CMOVE> test-MOVE> test-<MOVE ;

count bits in byte#

"BOUNDS" can be defined with:

( Convert str len to range for DO-loop )
: bounds ( str len -- str+len str )
  over + swap ;

"OFF" can be defined with:

( stores zero into address )
: OFF ( addr -- )
  0 SWAP ! ;
 \ Forth Benchmark - count bits in byte              cas 20101204
 
 VARIABLE cnt
 
 HEX 
 : countbits ( uu -- #bits )
   cnt off
   8 0 DO dup 01010101  and cnt +!
          2/
   LOOP drop
   0 cnt 4 bounds DO i C@ + LOOP ;
 
 DECIMAL
 
 : bench5
   8192 DO I countbits . LOOP ;

Sieve Benchmark#

FIG-Forth derived systems or Forth-79 Systems require the initial value of a variable on the stack.

So instead of "VARIABLE FLAGS 0 FLAGS !" use "0 VARIABLE FLAGS".

\ Sieve Benchmark -- the classic Forth benchmark    cas 20101204                   
                                                                                    
 8192 CONSTANT SIZE   
 VARIABLE FLAGS  
 0 FLAGS !  
 SIZE ALLOT                         
                                                                                    
 : DO-PRIME                                                                         
   FLAGS SIZE 1 FILL  ( set array )                                                 
   0 ( 0 COUNT ) SIZE 0                                                             
   DO FLAGS I + C@                                                                  
     IF I DUP + 3 + DUP I +                                                         
        BEGIN DUP SIZE <                                                            
        WHILE 0   OVER FLAGS +  C!  OVER +  REPEAT                                  
        DROP DROP 1+                                                                
     THEN                                                                           
 LOOP                                                                               
 . ." Primes" CR ;        

Greatest Common Divisor#

\ gcd - greatest common divisor                     cas 20101204                   
                                                                                    
 : gcd ( a b -- gcd )                                                               
   OVER IF                                                                          
     BEGIN                                                                          
       DUP WHILE                                                                    
          2DUP U> IF SWAP THEN OVER -                                               
     REPEAT DROP ELSE                                                               
     DUP IF NIP ELSE 2DROP 1 THEN                                                   
   THEN ;  
   
: gcd1-bench 100 0 DO 
      100 0 DO j i gcd drop loop
      loop ;  
\ another gcd O(2) runtime speed                    cas 20101204                   
                                                                                    
 : gcd2 ( a b -- gcd )                                                              
   2DUP        D0= IF  2DROP 1 EXIT   THEN                                          
   DUP          0= IF   DROP   EXIT   THEN                                          
   SWAP DUP     0= IF   DROP   EXIT   THEN                                          
   BEGIN  2DUP -                                                                    
   WHILE  2DUP < IF OVER -                                                          
                 ELSE SWAP OVER - SWAP                                              
                 THEN                                                               
   REPEAT NIP ;          

: gcd2-bench 100 0 DO 
      100 0 DO j i gcd2 drop loop
      loop ;  

Takeuchi#

( takeuchi benchmark in volksForth Forth-83 )
( see http://en.wikipedia.org/wiki/Tak_(function) )

DECIMAL

 : 3dup 2 pick 2 pick 2 pick ;                                                        

 : tak ( x y z -- t )                                                                 
   over 3 pick < NEGATE IF nip nip exit then                                          
   3dup rot 1- -rot recursive >r                                                      
   3dup swap 1- -rot swap recursive >r                                                
             1- -rot recursive                                                        
   r> swap r> -rot recursive ;                                                        
                                                                                      
 : takbench ( -- )                                                                    
   0 10000 0 DO DROP 18 12 6 tak LOOP ;                                            
                                                    

simple 6502 emulator#

\ A simple 6502 emulattion benchmark                         cas                     
\ only 11 opcodes are implemented. The memory layout is:                             
\  2kB RAM at 0000-07FF, mirrored throughout 0800-7FFF                               
\ 16kB ROM at 8000-BFFF, mirrored at C000                                            
decimal                                                                              
create ram 2048 allot   : >ram $7FF  and ram + ;                                     
create rom 16384 allot  : >rom $3FFF and rom + ;                                     
\ 6502 registers                                                                     
variable reg-a   variable reg-x  variable reg-y                                      
variable reg-s   variable reg-pc  : reg-pc+ reg-pc +! ;                              
\ 6502 flags                                                                         
variable flag-c  variable flag-n   variable cycle                                    
variable flag-z  variable flag-v  : cycle+ cycle +! ;                                
hex                                                                                  
: w@ dup c@ swap 1+ c@ 100 * or ;                                                    
: cs@ c@ dup 80 and if 100 - then ;        

: read-byte ( address -- )                                                           
  dup 8000 < if >ram c@ else >rom c@ then ;                                          
: read-word ( address -- )                                                           
  dup 8000 < if >ram w@ else >rom w@ then ;                                          
: dojmp ( JMP aaaa )                                                                 
  reg-pc @ >rom w@ reg-pc ! 3 cycle+ ;                                               
: dolda ( LDA aa )                                                                   
  reg-pc @ >rom c@ ram + c@ dup dup reg-a !                                          
  flag-z ! 80 and flag-n ! 1 reg-pc+ 3 cycle+ ;                                      
: dosta ( STA aa )                                                                   
  reg-a @ reg-pc @ >rom c@ ram + c! 1 reg-pc+ 3 cycle+ ;                             
: dobeq ( BEQ <aa )                                                                  
  flag-z @ 0= if reg-pc @ >rom cs@ 1+ reg-pc+ else 1 reg-pc+ then 3 cycle+ ;   
: doldai ( LDA #aa )                                                                 
  reg-pc @ >rom c@ dup dup reg-a ! flag-z ! 80 and flag-n !                          
  1 reg-pc+ 2 cycle+ ;                                                               
: dodex ( DEX )                                                                      
  reg-x @ 1- FF and dup dup reg-x ! flag-z ! 80 and flag-n !                         
  2 cycle+ ;                                                                         
: dodey ( DEY )                                                                      
  reg-y @ 1- ff and dup dup reg-y ! flag-z ! 80 and flag-n !                         
  2 cycle+ ;                                                                         
: doinc ( INC aa )                                                                   
  reg-pc @ >rom c@ ram + dup c@ 1+ FF and dup -rot swap c! dup                       
  flag-z ! 80 and flag-n !  1 reg-pc+ 3 cycle+ ;                                     
: doldy ( LDY aa )                                                                   
  reg-pc @ >rom c@ dup dup reg-y ! flag-z ! 80 and flag-n !                          
  1 reg-pc+ 2 cycle+ ; 
: doldx ( LDX #aa )                                                                  
  reg-pc @ >rom c@ dup dup reg-x ! flag-z ! 80 and flag-n !                          
  1 reg-pc+ 2 cycle+ ;                                                               
: dobne ( BNE <aa )                                                                  
  flag-z @ if reg-pc @ >rom cs@ 1+ reg-pc+ else 1 reg-pc+ then                       
  3 cycle+ ;                                                                         
: 6502emu ( cycles -- )                                                              
  begin cycle @ over  < while                                                        
    reg-pc @ >rom c@ 1 reg-pc+                                                       
    dup 4C = if dojmp then      dup A5 = if dolda then                               
    dup 85 = if dosta then      dup F0 = if dobeq then                               
    dup D0 = if dobne then      dup A9 = if doldai then                              
    dup CA = if dodex then      dup 88 = if dodey then                               
    dup E6 = if doinc then      dup A0 = if doldy then                               
        A2 = if doldx then      repeat drop ; 

create testcode                                                                      
  A9 c, 00 c,  \ start: LDA #0                                                       
  85 c, 08 c,  \        STA 08                                                       
  A2 c, 0A c,  \        LDX #10                                                      
  A0 c, 0A c,  \ loop1: LDY #10                                                      
  E6 c, 08 c,  \ loop2: INC 08                                                       
  88 c,        \        DEY                                                          
  D0 c, FB c,  \        BNE loop2                                                    
  CA c,        \        DEX                                                          
  D0 c, F6 c,  \        BNE loop1                                                    
  4C c, 00 c, 80 C, \   JMP start 
                                                     
: init-vm 13 0 do i testcode + c@ i rom + c! loop                                    
          0 cycle ! 8000 reg-pc ! ;                                                  

: bench6502 100 0 do init-vm &6502 6502emu loop ;