; BCPL Microcode for running Diablo Port Audio Terminal
; Last modified by L. Stewart: March 15, 1980  3:25 PM

; Microcode command file for Audio Terminal
; MU/l ATmc.mu
; PackMu ATmc.mb ATmc.br 160376   // Alto II
; PackMu ATmc.mb ATmc.br 177376   // Alto I

; Task assignments and BCPL emulator-routine entry points.

; Alto II version
%17,1777,0, Novem, L1, L2, L3, L4, L5, L6, L7, MRT, DWT, CURT, DHT, DVT, L15;

; Alto I version
; %17,1777,0, Novem, L1, L2, L3, L4, L5, L6, L7, MRT, L11, L12, L13, L14, L15;

%1,1777,20,Start;
%1,1777,21,AudioInit;
%1,1777,22,AudioStart;
%1,1777,23,AudioEnqueue;

#AltoConsts23.mu;

L1: TASK, :L1;
L2: TASK, :L2;
L3: TASK, :L3;
L4: TASK, :L4;
L5: TASK, :L5;
L6: TASK, :L6;
L7: TASK, :L7;
; L10: TASK, :L10;	Memory refresh task

; For Alto II, comment out L11, L12, L13, and L 14
; L11: TASK, :L11;	Display Word Task
; L12: TASK, :L12;	Cursor Task
; L13: TASK, :L13;	Display horizontal task
; L14: TASK, :L14;	Display Vertical Task

L15: TASK, :L15;

; For Alto I
; #CATMRT.mu;	contains MRT

; For Alto II
#CATIIMRT.mu;	contains MRT
#GateDisplay.mu;	contains DHT, DVT, CURT, DWT

;BCPL Emulator routines (via JMPRAM)
; Arg1 in AC0
; Ram Location	Routine
;	20	SetBLV -- Silent boot code (doesn't do the StartIO) for BCPL
;	21	AudioInit
;	22	AudioStart
;	23	AudioEnqueue

; Register definitions
$AC0	$R3;
$AC3	$R0;
$LastL	$R40;

$IACB	$R71;	input Audio Control Block
$IPtr	$R72;	data block pointer
$ICount	$R73;	word count
$RData	$R14;	input assembly register
$OACB	$R74;	output Audio Control Block
$OPtr	$R75;
$OCount	$R76;
$WData	$R15;	output word register
$NCount	$R60;

; Temporaries
$Temp2	$R63;
$Temp	$R16;	In Data

; Constants
$OREMask	$4000;
$DataMask	$170000;
$Strobe	$1;	command word strobe

; Silent boot interface

TStart:	TASK;
NStart:	NOP;
Novem:	SWMODE;
1Start:	:Start;

Start:	RMR _ AC0, :Novem;	Set RMR -- classical location for it

; This must run with MRT disabled (i.e. running in ROM)

AudioInit:	L _ 0;
	NCount _ L;
	IACB _ L;
	OACB _ L;
	OCount _ L;
	ICount _ L,TASK;
	WData _ L;

	T _ 177000;	Clear ready bit in hardware
	MAR _ 16 + T;
	L _ Strobe;
	MD _ LastL;
	MAR _ 16 + T;
	L _ 0, TASK;
	MD _ LastL,:NStart;

; On entry to AudioEnqueue, AC0 points to the new ACB, AC3 to the old

!1,2,Fail, Link;

AudioEnqueue:
	MAR _ AC3;
	L _ 0;
	SINK _ MD,BUS=0;
	MAR _ AC3+1,:Fail;	!1,2,Fail, Link;
Link:	NOP;
	MD _ AC0,TASK,:NStart;
Fail:	AC0 _ L,TASK,:NStart;

; AudioStart expects AC0 to be IACB and AC3 to be OACB.
;  n. b. A 0 starting value means none...
;
; Format of an ACB  (Even word aligned)
;   word 0:   Flags	Goes non-zero on completion
;   word 1:   Next ACB	pointer to next ACB
;   word 2:	Pointer	pointer to data block
;   word 3:	Count	size of block (in words)

AudioStart:	L _ AC0;
	IACB _ L;
	L _ AC3;
	OACB _ L;
	L _ 0;
	ICount _ L,TASK;
	OCount _ L,:Novem;

; This code runs as part of MRT

!1,2,Ready,NotYet;

AudioTest:	T _ 177000;
	MAR _ 30 + T;
	T _ OREMask;	two cycles here! (compute portout?)
	L _ T _ MD AND T;
	L _ DataMask AND T, SH=0;
	Temp2 _ L,:Ready;	!1,2,Ready,NotYet;

NotYet:	TASK;
	NOP,:ATDone;	back to MRT

!1,2,RightB,LeftB;
!1,2,IBMore,IBDone;
!1,2,ICMore,ICDone;
!1,2,OBMore,OBDone;
!1,2,OCMore,OCDone;

Ready:	;  write data
	T _ 177000;
	MAR _ 16 + T;
	T _ 177400;
	L _ WData AND T;
	MD _ LastL, TASK;
	Temp _ L;

	; Strobe it in
	T _ 177000;
	MAR _ 16 + T;
	L _ Temp + 1;	we know 1 is Strobe
	MD _ LastL;

;   Now read next nibble
	MAR _ 30 + T;	#177030
	T _ DataMask;
	L _ MD AND T,TASK;
	Temp _ L;

;  Turn off strobe
	T _ 177000;
	MAR _ 16 + T;
	T _ 177400;
	L _ WData AND T, TASK;
	MD _ LastL;

	L _ Temp, TASK;
	Temp _ L RSH 1;
	L _ Temp, TASK;
	Temp _ L RSH 1;
	L _ Temp, TASK;
	Temp _ L RSH 1;
	L _ Temp, TASK;
	Temp _ L RSH 1;
	T _ Temp;
	L _ Temp2 OR T, TASK;
	Temp _ L;
; Now input byte is left justified in Temp

	SINK _  NCount, BUS=0;
	L _ 0,:RightB;	!1,2,RightB,LeftB;

;Assume Temp holds left justified nibble.

; Left Byte
LeftB:	L _ ALLONES;
	NCount _ L;
	L _ Temp, TASK;
	RData _ L LCY 8;
	L _ WData,TASK;	swab WData
	WData _ L LCY 8,:ATDone;

; Right byte
RightB:	NCount _ L;
	T _ RData;
	L _ Temp OR T, TASK;
	RData _ L LCY 8,:WTIn;

; Once per word code (250 microseconds)

WTIn:	L _ ICount-1, BUS=0, TASK;	decrement input count
	ICount _ L,:IBMore;	!1,2,IBMore,IBDone; (input block)

; Block completion, input

IBDone:	MAR _ L _ IACB,BUS=0;
	T _ 2,:ICMore;	!1,2,ICMore,ICDone; (input chain)
ICMore:	MD _ LastL;
	L _ MD;
	MAR _ LastL+T;
	IACB _ L;
;	predecrement ptr because we increment it before use
	L _ MD - 1;
;	we test count  for zero before decrementing it
;	since we are starting a new block, ICount must be decremented
;	to account for the store in IBMore below.
	T _ MD - 1;
	IPtr _ L, L _ T, TASK;
	ICount _ L,: IBMore;

ICDone:	L _ 0, TASK;	leave count at 0
	ICount _ L,:WTOut;

IBMore:	MAR _ L _ IPtr+1;	we increment ptr before use
	IPtr _ L;
	L _ RData, TASK;
	MD _ LastL,:WTOut;

WTOut:	L _ OCount-1, BUS=0, TASK;	decrement output count
	OCount _ L,:OBMore;	!1,2,OBMore,OBDone;

; Block completion, output

OBDone:	MAR _ L _ OACB,BUS=0;
	T _ 2,:OCMore;	!1,2,OCMore,OCDone;
OCMore:	MD _ LastL;
	L _ MD;
	MAR _ LastL+T;
	OACB _ L;
;	predecrement ptr because we increment it before use
	L _ MD - 1;
;	we test count  for zero before decrementing it
;	OCount must be decremented to account for the fetch in
;	OBMore below.
	T _ MD - 1;
	OPtr _ L, L _ T, TASK;
	OCount _ L,: OBMore;

OCDone:	L _ 0;
	WData _ 0, TASK;
	OCount _ L,:ATDone;	leave count at 0

OBMore:	MAR _ L _ OPtr+1;
	OPtr _ L;
	L _ MD, TASK;
	WData _ L,:ATDone;

;; December 24, 1979  5:59 PM L. Stewart.  created file
;; December 25, 1979  8:18 PM L. Stewart.  task code
;; December 28, 1979  10:43 PM L. Stewart.  new design
(0,5376)(1,11264)\f1