This is an old revision of the document!
Clock-Cycle Counter Register is a new SAGA Read-Only register. It is unique feature, never seen in other 68K existing system. It allows to get, in real-time, the number of cycles consumed by one or more CPU instructions. This register can come in handy when programmer need to optimize his code and locate greedy routines.
Each time register is read, the
internal counter is reinitialized to 0.
overflow if the delay between two calls is too long.
TEST: move.l #$CAFECAFE,d1 ; Operand for DIVU.L tst.l $DE0008 ; Reset the Clock-Cycle counter divu.l #100,d1 ; Consume some CPU cycles move.l $DE0008,d0 ; D0 = Number of cycles consumed by the DIVU instruction. rts
DEBUG EQU 1 SAGA_CLOCK_COUNTER EQU $DE0008 CLKCNT_RESET MACRO IFNE DEBUG tst.l SAGA_CLOCK_COUNTER ENDC ENDM CLKCNT_SAVE MACRO IFNE DEBUG move.l SAGA_CLOCK_COUNTER,__\1 ENDC ENDM CLKCNT_ADD MACRO IFNE DEBUG move.l d0,-(sp) move.l SAGA_CLOCK_COUNTER,d0 add.l d0,__\1 move.l (sp)+,d0 ENDC ENDM
MyRoutine: move.l #$CAFECAFE,d1 ; Operand for DIVU CLKCNT_RESET ; Reset the Clock-Cycle counter divu.l #100,d1 ; Consume some CPU cycles CLKCNT_SAVE MyCounter ; Save the number of cycles in MyCounter RTS MyCounter: DC.L 0