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Cycles/Timing


42bs

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Did some measurements (after all these year ... ?  )

;                    75Hz          |        60Hz           |        50Hz
; iter opcode  count   us   cycles | count    us   cycles  | count    us   cycles |
;              of 64us  per opcode | of 64us  per opcode   | of 64us  per opcode  |
; ---------------------------------------------------------------------------------
; 32K  xb,x3    152   0.297   1    |  148    0.289    1	   |  145    0.283    1
; 16K  NOP      152   0.594   2    |  147    0.578    2	   |  144    0.563    2
; 16K  x2       152   0.594   2	   |	 		   |
; 16K  adc imm  152   0.594   2    |			   |
;  8K  adc zp   130   1.02    3.4  |			   |
;  8K  adc abs  169   1.32    4.4  |  163    1.27     4.4  |
;  8K  jmp      122   0.953   3.2  |			   |
;  8K  bra      122   0.953   3.2  |			   |
;  8K  bCC n/t   76   0.598   2.1  |			   |
;  8K  bCC  /t  122   0.953   3.2  |			   |
;  8K  $dc,$fc  169   1.32    4.4  |			   |
;  4K  $5c      177   2.77    2.6  |			   |
;  4K  inc abs  130   2.03    6.8  |			   |
;  4K  inc zp   111   1.73    5.8  |			   |

; n/t not taken
;  /t taken

One can see the influence of the screen refresh on the length of a cycle and also that the clock of the CPU is ~3.5MHz (not 4MHz).

Code: https://github.com/42Bastian/lynx_hacking/tree/master/cycle_check

Edited by 42bs
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