Subject:
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RE: Finally able to add asm forth words (long)
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Newsgroups:
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lugnet.robotics.rcx.pbforth
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Date:
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Mon, 22 May 2000 14:39:32 GMT
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Viewed:
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1363 times
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Steve Morris wrote:
> By the way my primary tool for creating the assembler is write the
> first pass in C and use gcc -S. My primary source of inspiration is
> lnp-logical.c although I have to take care to extract rx from tx. For
> example I follow lnp-logical.c's lead on figuring out about where the
> interrupt vectors are redirected by the ROM.
Steve,
You ARE using Kekoa's Internals document, right? Here's the part
that describes the interrupt vector redirection. In fact, that's
what I do for grabbing the OC1B interrupt for the servo control words...
remember intercepting the keyboard interrupt for TSRs under DOS?
Here is some information that might be useful...study it carefully
grasshopper :-) I think I can get away with this since you are about
the same age I am and remember the series "Kung Fu", right?
Here is the prototype interrupt service routine...
;------------------------------------------------------------------------------
; OCIBisr is a routine that will handle expiries on the OC1B comparator. Its
; job is to set the motor currently being processed to the correct state.
OCIBisr:
MOV.W rA,@-rDSP ; Save any registers we'll use
BCLR #2,@H8_TIER:8 ; Disallow OCRB interrupts
BCLR #2,@H8_TCSR:8 ; Clear pending OCRB interrupts
MOV.W @SERVOidx,rA ; Figure out which motor we're on
XOR.B rAh,rAh
ADD.W rA,rA ; Set up pointer to servo data
MOV.W @(SERVO_IDX,rA),rA
OCIB1: MOV.B @(9,rA),rAh ; Grab the default setting for the motor
MOV.B @0xEFCA,rAl ; Force motor to proper FWD/REV state
OR.B rAh,rAl ; OR since OFF was zeros!
MOV.B rAl,@0xEFCA ; Save unmodulated motor state
MOV.B rAl,@0xEFCE ; Save modulated motor state for the real OC1A
MOV.B rAl,@0xF000 ; Write result to motor drivers
MOV.W @rDSP+,rA
RTS
;------------------------------------------------------------------------------
; SERVO_INIT ( -- )
;
; This uses the exact same dispatch code as the RCX has in the ROM...it
; assumes that the handler saves all of the resisters it uses, but comes
; back to the caller via an RTS. The ROM routine we vectored through does
; the RTE for us!!!
;
; Knowing this, we can just load R6 (because that's the one the dispatch
; routine saved) and JSR into the old vector...
OCIAsave: .word 0x0000
;------------------------------------------------------------------------------
M_CODE(10,``"SERVO_INIT"'',SERVO_INIT,_SLINK)
MOV.W @OCIA_VECTOR,rA ; Grab the current OCIA vector
MOV.W #0x36BA,rB ; Check if it's been "wedged" already
CMP.W rA,rB
BNE WDG1 ; And exit if it has
MOV.W rA,@OCIAsave ; And save it
MOV.W #OCIAwedge,rA ; Now set our routine to run first
MOV.W rA,@OCIA_VECTOR
MOV.W #OCIBisr,rA ; Now set our routine to run first
MOV.W rA,@OCIB_VECTOR
WDG1:
M_NEXT()
;------------------------------------------------------------------------------
And here are the redirect vectors in RAM:
fd90 - word, like a reset vectorfd92 - word, NMI interrupt vector
fd94 - word, IRQ0 interrupt vectorfd96 - word, IRQ1 interrupt vector
fd98 - word, IRQ2 interrupt vectorfd9a - word, ICIA interrupt vector
fd9c - word, ICIB interrupt vectorfd9e - word, ICIC interrupt vector
fda0 - word, ICID interrupt vector
fda2 - word, OCIA interrupt vector, set to 36ba by 3b9a
fda4 - word, OCIB interrupt vectorfda6 - word, FOVI interrupt vector
fda8 - word, CMI0A interrupt vectorfdaa - word, CMI0B interrupt vector
fdac - word, OVI0 interrupt vectorfdae - word, CMI1A interrupt vector
fdb0 - word, CMI1B interrupt vectorfdb2 - word, OVI1 interrupt vector
fdb4 - word, ERI interrupt vector, set to 30a3 at 31ec
fdb6 - word, RXI interrupt vector, set to 2c10 at 31e4
fdb8 - word, TXI interrupt vector, set to 2aac at 31dc
fdba - word, TEI interrupt vector, set to 2a84 at 31d4
fdbc - word, A/D interrupt vector, set to 3b74 by 3b9a
fdbe - word, WOVF interrupt vector
;------------------------------------------------------------------------------
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Message has 1 Reply:
Message is in Reply To:
 | | Re: Finally able to add asm forth words.
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| (...) It puzzled me for quite a while until I realized that the output was in pbforth.s. Once I saw the results it was much easier. (...) I agree. I have no interest in supporting a varient. I'll hack until it seems to work and then pass it to you (...) (24 years ago, 22-May-00, to lugnet.robotics.rcx.pbforth)
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