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saga:registers:saga_clock_counter [2019/10/21 12:32] muaddib ↷ Links adapted because of a move operation |
saga:registers:saga_clock_counter [2020/08/02 12:37] |
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| - | ====== SAGA Clock-Cycle Register ====== | ||
| - | {{:clockcycle.png?64|}} | ||
| - | ===== Overview ===== | ||
| - | |||
| - | ''Clock-Cycle 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. | ||
| - | |||
| - | ---- | ||
| - | |||
| - | ===== Name ===== | ||
| - | |||
| - | * ''SAGA_CLOCK_COUNTER'' | ||
| - | |||
| - | ===== Address ===== | ||
| - | |||
| - | * ''0xDE0008'' | ||
| - | |||
| - | ===== Access ===== | ||
| - | |||
| - | * ''Read-Only'' | ||
| - | |||
| - | ===== Size ===== | ||
| - | |||
| - | * ''32-bits'' | ||
| - | |||
| - | ---- | ||
| - | |||
| - | ===== Description ===== | ||
| - | |||
| - | Each time register is read, the ''internal counter'' is reinitialized to 0. | ||
| - | |||
| - | Can ''overflow'' if the delay between two calls is too long. | ||
| - | |||
| - | ---- | ||
| - | |||
| - | ===== Example ===== | ||
| - | |||
| - | 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 | ||
| - | |||
| - | ---- | ||
| - | |||
| - | ===== Macros ===== | ||
| - | |||
| - | 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 | ||
| - | |||
| - | ---- | ||
| - | |||
| - | [[start|Home]] | | ||
| - | [[links|Links]] | | ||
| - | [[saga:start|SAGA]] | | ||
| - | [[saga_core_registers|SAGA Registers]] | ||
Last modified: le 2020/08/02 12:37
