+@ updates fceu "timestamp" variable
+@ loads cycles to reg, reg!=r1, trashes r1, kills flags
+.macro FLUSH_TIMESTAMP reg
+ ands \reg, REG_CYCLE, #0xff
+ beq 1f
+ ldr r1, [REG_OP_TABLE, #OTOFFS_TIMESTAMP]
+ orr REG_CYCLE, REG_CYCLE, \reg, lsl #8 @ put cycles for do_irq_hook
+ add r1, r1, \reg
+ bic REG_CYCLE, REG_CYCLE, #0xff
+ str r1, [REG_OP_TABLE, #OTOFFS_TIMESTAMP]
+1:
+.endm
+