diff --git a/README.md b/README.md
index ba15358..7ad65a0 100644
--- a/README.md
+++ b/README.md
@@ -1,2 +1,47 @@
 # puce65c02
-puce65c02, a WDC 65c02 cpu emulator
+puce65c02, a WDC 65c02 cpu emulator focusing on accuracy and performance
+runs at ~1Ghz on a modern computer
+powers reinette IIe : https://github.com/ArthurFerreira2/reinetteIIe
+
+### tests
+I left the test and timing routines I used during developpement 
+you can use them to verify accuracy :
+
+Theses tests require `6502_functional_test.bin` and `65C02_extended_opcodes_test.bin` which you can get from https://github.com/Klaus2m5/6502_65C02_functional_tests
+and `timingtest-1.bin` I got from BigEd at http://forum.6502.org/viewtopic.php?f=8&t=3340
+
+### compile and run :
+```bash
+g++ -Wall -O3 -D __TESTS__ puce65c02.cpp -o puce65c02 && ./puce65c02
+```
+or, much slower but with detailled info :
+
+```bash
+g++ -Wall -O3 -D __TESTS__ -D VERBOSE puce65c02.cpp -o puce65c02 && ./puce65c02
+```
+or, if you just want to check the cycle accuracy :
+
+```bash
+g++ -Wall -O3 -D __TESTS__ -D TIMING puce65c02.cpp -o puce65c02 && ./puce65c02
+```
+
+### sample run :
+```
+360F 08        PHP              A=24  X=0E  Y=FF  S=FB  *S=0E  --UB----  Cycles: 3 Total: 3101022
+3610 C5 0F     CMP $0F          A=24  X=0E  Y=FF  S=FB  *S=0E  --UB--ZC  Cycles: 3 Total: 3101025
+3612 D0 FE     BNE $FE          A=24  X=0E  Y=FF  S=FB  *S=0E  --UB--ZC  Cycles: 2 Total: 3101027
+3614 68        PLA              A=30  X=0E  Y=FF  S=FC  *S=30  --UB---C  Cycles: 4 Total: 3101031
+3615 29 C3     AND #$C3         A=00  X=0E  Y=FF  S=FC  *S=30  --UB--ZC  Cycles: 2 Total: 3101033
+3617 C5 11     CMP $11          A=00  X=0E  Y=FF  S=FC  *S=30  --UB--ZC  Cycles: 3 Total: 3101036
+3619 D0 FE     BNE $FE          A=00  X=0E  Y=FF  S=FC  *S=30  --UB--ZC  Cycles: 2 Total: 3101038
+361B 28        PLP              A=00  X=0E  Y=FF  S=FD  *S=72  -VUB--Z-  Cycles: 4 Total: 3101042
+361C 08        PHP              A=00  X=0E  Y=FF  S=FC  *S=30  -VUB--Z-  Cycles: 3 Total: 3101045
+361D A5 12     LDA $12          A=F6  X=0E  Y=FF  S=FC  *S=30  NVUB----  Cycles: 3 Total: 3101048
+361F 8D 1502   STA $0215        A=F6  X=0E  Y=FF  S=FC  *S=30  NVUB----  Cycles: 4 Total: 3101052
+3622 A5 0D     LDA $0D          A=1B  X=0E  Y=FF  S=FC  *S=30  -VUB----  Cycles: 3 Total: 3101055
+3624 20 1402   JSR $0214        A=1B  X=0E  Y=FF  S=FA  *S=00  -VUB----  Cycles: 6 Total: 3101061
+0214 E9 F6     SBC #$F6         A=24  X=0E  Y=FF  S=FA  *S=00  --UB----  Cycles: 2 Total: 3101063
+0216 60        RTS              A=24  X=0E  Y=FF  S=FC  *S=36  --UB----  Cycles: 6 Total: 3101069
+```
+
+enjoy !