Re: hi-way fuel and mask 88h

[rrauscher@nni.com]

A light just went on! Yes, I see exactly what you are saying.
They are calculating an accurate air flow term. Much more
accurate than the 'ole map * rpm used elsewhere.

Here is the code I am referring to:

; called from above
;
; L0186 ~= (BPW * 26,160) * (C0h CylMsk * 200) * (rpm * AFR)
; (with some divide by 65536's in there)
;    
LC456: FE 01 59      LDX         L0159		; closed loop corrected BPW
LC459: B6 8E 3D      LDAA        L8E3D		; == 120d
LC45C: C6 DA         LDAB        #218
LC45E: 3D            MUL  			; AB == 26,160
LC45F: BD F5 30      JSR         LF530		; 16x16 mult: AB = (X x AB)
LC462: 37            PSHB 
LC463: 36            PSHA 
LC464: 30            TSX  
LC465: B6 80 09      LDAA        L8009		; == C0h, cylinders mask
LC468: C6 C8         LDAB        #200
LC46A: 3D            MUL  			; AB = 38,400
LC46B: BD F5 D7      JSR         LF5D7		; 8 x 16 mult: AB = (*X * A)
LC46E: ED 00         STD         0,X		; move result to X
LC470: 38            PULX 			; X has result so far
;
;
LC471: 96 87         LDAA        L0087		; desired afr * 10
LC473: D6 61         LDAB        L0061		; rpm / 25
LC475: 3D            MUL  			; AB = A * B (afr * rpm)
LC476: BD F5 30      JSR         LF530		; 16x16 mult: AB = (X x AB)
LC479: 4D            TSTA 
LC47A: 27 02         BEQ         LC47E		; bra if A == 0
LC47C: C6 FF         LDAB        #255
;
LC47E: 17            TBA  			; A == B, keep LSB
LC47F: 3C            PSHX 
LC480: 33            PULB 			; B == MSB of X
LC481: 31            INS  			; fake PUL
LC482: 05            LSLD 			; AB *= 2
LC483: 24 02         BCC         LC487
LC485: 86 FF         LDAA        #255
;
LC487: FD 01 86      STD         L0186		; save what we have
;


BobR.

p.s. I onto the remaining fuel routines such as hi-way. Found
that I had deleted several hundred lines of code, somehow.
Can't find something that isn't there!

>
>>I understand what you are saying, the airflow calc uses a map value
>>and rpm terms. What throws me on this one is the mix of bpw and afr,
>>along with the cylinders mask!
>
>I was looking at my ATTA disassembly and I think I've found what your 
>talking about.  Starting at line 43AE, I start multiplying things together

>including RPM, AFR, Cylinder mask, amongst others. Are we on the same page

>here, or is this another section of code?
>
>RPM * BPW is proportional to fuel flow rate.  Multiply that by AFR and you

>have Air flow rate.
>
>>A quick look at it shows that it appears to be mostly a load value
>>and engine speed term.
>
>Are you sure it's not airflow?  It fits what you just described...
>
>Ya wanna send me a chunk of code so I can compare?
>Thanks
>
>Jeremy
>
>
>
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