Re: [Sdcc-user] SDCC DS390 Port and _sdcc_external_startup

[Arif M. <Ari...@sd...>]

>> (* please forgive the top-post *)

>> Arif --

>> >>>   P1 = 0xFF; //ALL LEDs off
>> >>>   P1 &= (0x1<<4); //LED 4 ON


>> Try:
>>     P1 &= ~(1<<4) ;    // LED 4 on.

>> your code was turning off LED4.  The tilde (~) creates a bitmask that
>> will preserve the P1 bits.  They will stay off.


>> well, it is just a guess.  I am more of a Z80 programmer....


>> HTH,
>> *the other brian



---------------------------------------------------

Hello brian,

Thanks for your response.

Ah! The typo. Your observation is right. But this mistake was only in my email. The code has the correct expression (i.e. P1 &= ~(1<<4)).

Also, I checked the hello390.asm file and the assembly code seems as expected
----------------------------------------------------------------------------------
__reset_vect:
	ljmp	__sdcc_gsinit_startup
;--------------------------------------------------------
; global & static initialisations
;--------------------------------------------------------
	.area HOME    (CODE)
	.area GSINIT  (CODE)
	.area GSFINAL (CODE)
	.area GSINIT  (CODE)
__sdcc_gsinit_startup:
	mov	sp,#__start__stack - 1
	lcall	__sdcc_external_startup
	mov	a,dpl
	jz	__sdcc_init_data
	ljmp	__sdcc_program_startup
----------------------------------------------------------------------------------


Here, after reset __sdcc_gsinit_startup is called and then after adjusting the stack pointer; __sdcc_external_startup is called.

----------------------------------------------------------------------------------
;	 function _sdcc_external_startup
;	-----------------------------------------
__sdcc_external_startup:
	ar2 = 0x02
	ar3 = 0x03
	ar4 = 0x04
	ar5 = 0x05
	ar6 = 0x06
	ar7 = 0x07
	ar0 = 0x00
	ar1 = 0x01
;	hello390.c:8: WTST = 0x00;
;	genAssign: resultIsFar = FALSE
	mov	_WTST,#0x00
;	hello390.c:9: CKCON = 0x01;
;	genAssign: resultIsFar = FALSE
	mov	_CKCON,#0x01
;	hello390.c:12: P1 = 0xFF;	
;	genAssign: resultIsFar = FALSE
	mov	_P1,#0xFF
;	hello390.c:13: P1 &= ~(0x1<<4);
	anl	_P1,#0xEF
--------------------------------------------------------------------------------------

The above shown code for __sdcc_external_startup seems correct too. If the control reaches here correctly, the LED must start to glow but it doesn't.
So it seems the control is not reaching inside __sdcc_external_startup.

Only suspicious thing which I can see is that __sdcc_external_startup is not in HOME seg (0x00-0x4D == 77 bytes) instead it is in CODE seg (s_CSEG == 0x008D).


Thanks
Arif