ISSUE – Destination and RAM access bit specified

This used to be requried for asm code when you wanted to tell it the ,d and ,a bits of the instruction:


near static unsigned char uc_asm_irq_temp;		// near qualifier specifies access RAM
near static unsigned char uc_asm_irq_temp1;

		movlw	0xcb
		addwf	_uc_asm_irq_temp,f,c			//(1 = file register, 0 = access ram)
		movlw	0xf3
		addwfc	_uc_asm_irq_temp1,f,c			//(1 = file register, 0 = access ram)

In a Microchip lets make like difficuilt for programmers step the 1 and 0 values the PIC device datasheets specify for theser bits can'#t actually be used, so ,f and ,c have to be used instead,  However not they don's seem to work either (2017-05) and to get the instructions above to work properly we have to change them to this:


		movlw	0xcb
		addwf	_uc_asm_irq_temp
		movlw	0x63
		addwfc	_uc_asm_irq_temp1

So the full code in our heartbeat timer which works is now:


		#asm
		GLOBAL _uc_asm_irq_temp
		GLOBAL _uc_asm_irq_temp1
		//Reset timer for next rollover
		movff	TMR0L,_uc_asm_irq_temp			//read_current_timer_value (read low byte loads high byte)
		movff	TMR0H,_uc_asm_irq_temp1
		movlw	0xcb
		addwf	_uc_asm_irq_temp
		movlw	0x63
		addwfc	_uc_asm_irq_temp1
		movff	_uc_asm_irq_temp1,TMR0H			//Store new value (high byte first)
		movff	_uc_asm_irq_temp,TMR0L
		#endasm

 

 

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