; Copyright 1996 Acorn Computers Ltd
;
; Licensed under the Apache License, Version 2.0 (the "License");
; you may not use this file except in compliance with the License.
; You may obtain a copy of the License at
;
; http://www.apache.org/licenses/LICENSE-2.0
;
; Unless required by applicable law or agreed to in writing, software
; distributed under the License is distributed on an "AS IS" BASIS,
; WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
; See the License for the specific language governing permissions and
; limitations under the License.
;
; > $.Source.VduDecl
; ARTHUR OPERATING SYSTEM - Vdu Drivers
; =======================
;
; Vdu driver workspace and macro declarations
;
; Author R C Manby
; Date 5.9.86
;
GBLL ForceMark ; whether we force start of mark state
ForceMark SETL {FALSE} ; of cursor on exit from WRCH
GBLL RePlot ; Re-plot cursor after wrch
RePlot SETL {TRUE}
GBLL UseVLineOnSolidLines ; When TRUE VLine is assembled and used
UseVLineOnSolidLines SETL {TRUE} ; to plot vertical solid lines
GBLL AvoidScreenReads ; When TRUE, use extra code to avoid
AvoidScreenReads SETL {TRUE} ; reading the screen when we can avoid it
GBLL DefaultSupremacy ; When TRUE, 16bpp and 32bpp modes' default
DefaultSupremacy SETL {FALSE} ; palettes use top bits for supremacy
;
; Register usage
; ==============
;
StkPtr RN 13 ;Restore on exit to keep BASIC happy!!
Link RN 14
;
; Manifest constants
; ==================
;
; To change the order of mode variables, change the following:-
; a) The order of the 'wk' labels below
; b) The order of the output variables in macro VWSTAB
; c) The order of the variables in '$.Hdr.Workspace' and '$.Hdr.NewSpace'
^ 0
wkstart # 0
; values which are calculated from sprite header when switching to sprite
wkScreenSize # 4
wkXWindLimit # 4
wkYWindLimit # 4
wkLineLength # 4
wkmiddle # 0
; values which are taken from pushed mode info (from wkmiddle ... wkmidend)
wkNColour # 4
wkYShftFactor # 4
wkModeFlags # 4
wkXEigFactor # 4
wkYEigFactor # 4
wkLog2BPC # 4
wkLog2BPP # 4
wkmidend # 0
; these are also taken from sprite header
wkScrRCol # 4
wkScrBRow # 4
wkend # 0
wksize * wkend-wkstart
wkwordsize * (wksize + 3) :AND: :NOT: 3
PushedInfoSize * wkwordsize + VIDCList3Size
NumModes * 54
maxmode * NumModes-1
; Reason codes for generalised DAG interface
; Layout of palette space
PalEntries * 256+1+3
^ 0
Pal_Blank # PalEntries*4 ; Blank palette (for screen saver)
Pal_LogFirst # PalEntries*4 ; Logical palette (as read/written by user)
Pal_LogSecond # PalEntries*4
Pal_PhysFirst # PalEntries*4 ; Physical palette (post transfer function)
Pal_PhysSecond # PalEntries*4
Pal_RTable # 256 ; Logical->physical lookup tables for R,G,B,S
Pal_GTable # 256
Pal_BTable # 256
Pal_STable # 256
Pal_Blocksize # 0
; GraphicsV driver state
; For each allocated driver number, the corresponding word of GraphicsVDrivers
; points to an instance of the following structure:
^ 0
GVDriver_RegisterFlags # 4 ; Flags on registration
GVDriver_Name # 4 ; Name on registration
GVDriver_StateFlags # 4 ; Current state flags
GVDriver_Size # 0
GVDriverState_Started * 1:SHL:0 ; ScreenMode_StartDriver called
;
; Macro Definitions
; =================
;
;
; Macro Sort - Sort two values into increasing order
;
MACRO
Sort $lo, $hi
CMP $hi, $lo
EORLT $lo, $lo, $hi
EORLT $hi, $lo, $hi
EORLT $lo, $lo, $hi
MEND
;
; Macro SortT - Sort two values into increasing order using a temporary reg
;
MACRO
SortT $lo, $hi, $temp
SUBS $temp, $hi, $lo
MOVLT $hi, $lo
ADDLT $lo, $lo, $temp
MEND
;
; Macro CompSwap - Compare and sort a pair of coordinates into
; order of increasing Y
; If Y values equal, sort in order of decreasing X
;
MACRO
CompSwap $xl,$yl, $xh,$yh
CMP $yh, $yl
EORLT $yl, $yl, $yh
EORLT $yh, $yl, $yh
EORLT $yl, $yl, $yh
CMPEQ $xl, $xh
EORLT $xl, $xl, $xh
EORLT $xh, $xl, $xh
EORLT $xl, $xl, $xh
MEND
;
; Macro CompSwapT - Compare and sort a pair of coordinates into
; order of increasing Y
; If Y values equal, sort in order of decreasing X
; Uses a temporary register
;
MACRO
CompSwapT $xl,$yl, $xh,$yh, $temp
SortT $yl, $yh, $temp
CMPEQ $xl, $xh
EORLT $xl, $xl, $xh
EORLT $xh, $xl, $xh
EORLT $xl, $xl, $xh
MEND
;
; Macro Difference - rc := ABS(ra-rb)
;
; Test GE/LT for ra>=rb / ra<rb
;
MACRO
Difference $rc,$ra,$rb
SUBS $rc,$ra,$rb
RSBLT $rc,$rc,#0
MEND
;
; Macro Least - Select the smallest value (signed)
;
MACRO
Least $rc,$ra,$rb
CMP $ra,$rb
[ $rc = $ra
|
MOVLE $rc,$ra
]
[ $rc = $rb
|
MOVGT $rc,$rb
]
MEND
;
; Macro Greatest - Select the largest (signed) value
;
MACRO
Greatest $rc,$ra,$rb
CMP $ra,$rb
[ $rc = $ra
|
MOVGE $rc,$ra
]
[ $rc = $rb
|
MOVLT $rc,$rb
]
MEND
;
; Macro PackXtnd - pack 2 bytes into 1 word and sign extend
;
MACRO
PackXtnd $result,$hi,$lo
[ $lo = $result
ADD $result,$lo,$hi,LSL #8
MOV $result,$result,LSL #16
MOV $result,$result,ASR #16
|
MOV $result,$hi,LSL #24
ORR $result,$lo,$result,ASR #16
]
MEND
MACRO
LoadCoordPair $x, $y, $basereg, $offset
[ NoARMv4 :LOR: (($offset :AND: 1)=1)
[ NoARMv6 :LOR: NoUnaligned
ASSERT $x < $y
[ ($offset) :AND: 3 = 2
ADD $x, $basereg, #($offset)-2
LDMIA $x, {$x, $y} ; (Xh,Xl,??,??) (??,??,Yh,Yl)
MOV $x, $x, ASR #16 ; (Xs,Xs,Xh,Xl)
[ NoARMv6
MOV $y, $y, LSL #16 ; (Yh,Yl, 0, 0)
MOV $y, $y, ASR #16 ; (Ys,Ys,Yh,Yl)
|
SXTH $y, $y ; (Ys,Ys,Yh,Yl)
]
|
[ ($offset) :AND: 3 = 0
LDR $x, [$basereg, #$offset] ; (Yh,Yl,Xh,Xl)
|
[ ($offset) :AND: 3 = 1
ADD $x, $basereg, #($offset)-1
LDMIA $x, {$x, $y} ; (Yl,Xh,Xl,??) (??,??,??,Yh)
MOV $x, $x, LSR #8 ; ( 0,Yl,Xh,Xl)
ORR $x, $x, $y, LSL #24 ; (Yh,Yl,Xh,Xl)
|
ADD $x, $basereg, #($offset)-3
LDMIA $x, {$x, $y} ; (Xl,??,??,??) (??,Yh,Yl,Xh)
MOV $x, $x, LSR #24 ; ( 0, 0, 0,Xl)
ORR $x, $x, $y, LSL #8 ; (Yh,Yl,Xh,Xl)
]
]
MOV $y, $x, ASR #16 ; (Ys,Ys,Yh,Yl)
[ NoARMv6
MOV $x, $x, LSL #16 ; (Xh,Xl, 0, 0)
MOV $x, $x, ASR #16 ; (Xs,Xs,Xh,Xl)
|
SXTH $x, $x ; (Xs,Xs,Xh,Xl)
]
]
|
; Use unaligned loads from ARMv6
LDRSH $x, [$basereg, #$offset]
LDRSH $y, [$basereg, #($offset)+2]
]
|
; Aligned halfwords
LDRSH $x, [$basereg, #$offset]
LDRSH $y, [$basereg, #($offset)+2]
]
MEND
;
; Macro SaveRetAdr - Push R14 to our pseudo stack
;
MACRO
SaveRetAdr
Push R14
MEND
;
; Macro Return - Pull from stack into PC
;
MACRO
Return $cond
LDR$cond PC, [StkPtr], #4
MEND
;
; Macro WINDow - Compare coordinate against graphics window
;
; Test GE/LT for within/outside window
;
MACRO
WINDow $rx,$ry, $rl,$rb,$rr,$rt
; ASSERT ($rl < $rb) AND ($rb < $rr) AND ($rr < $rt)
ADD $rt,WsPtr,#GWLCol
LDMIA $rt,{$rl,$rb,$rr,$rt}
CMP $rx,$rl
CMPGE $rr,$rx
CMPGE $ry,$rb
CMPGE $rt,$ry
MEND
;
; Macro WindowRes - Window a coordinate, giving status word
;
; Result word is as follows:
;
; | |
; 1001 | 1000 | 1010
; | |
; -----+------+----- GWTRow
; | |
; 0001 | 0000 | 0010
; | |
; -----+------+----- GWBRow
; | |
; 0101 | 0100 | 0110
; | |
;
; GWLCol GWRCol
;
;
MACRO
WindowRes $result, $rx,$ry, $rl,$rb,$rr,$rt
; ASSERT ($rl < $rb) AND ($rb < $rr) AND ($rr < $rt)
MOV $result,#0
ADD $rt,WsPtr,#GWLCol
LDMIA $rt,{$rl,$rb,$rr,$rt}
CMP $rx,$rl
ORRLT $result,$result,#1 ;Set bit 0 if X < window
CMP $rr,$rx
ORRLT $result,$result,#2 ;Set bit 1 if X > window
CMP $ry,$rb
ORRLT $result,$result,#4 ;Set bit 2 if Y < window
CMP $rt,$ry
ORRLT $result,$result,#8 ;Set bit 3 if Y > window
MEND
MACRO
$lab EQUB $var
ASSERT $var >= &00
ASSERT $var <= &FF
$lab = $var
MEND
MACRO
OrrEor $d,$s, $or,$eor
ORR $d,$s,$or
EOR $d,$d,$eor
MEND
MACRO ;Scr:=ScrOR(oraANDmsk)EOR(eorANDmsk)
OrrEorMASK $scr,$msk, $ora,$eor, $tmp
AND $tmp,$msk,$ora
ORR $scr,$scr,$tmp
AND $tmp,$msk,$eor
EOR $scr,$scr,$tmp
MEND
MACRO
ORoreorEORoreor $d,$s, $oo,$eo,$oe,$ee, $tmp
OrrEor $tmp,$s, $oo,$eo
ORR $d,$d,$tmp
OrrEor $tmp,$s, $oe,$ee
EOR $d,$d,$tmp
MEND
MACRO
ORoreorEORoreorMASK $d,$s,$m, $oo,$eo,$oe,$ee, $tmp
OrrEor $tmp,$s, $oo,$eo
AND $tmp,$tmp,$m
ORR $d,$d,$tmp
OrrEor $tmp,$s, $oe,$ee
AND $tmp,$tmp,$m
EOR $d,$d,$tmp
MEND
MACRO
ShiftR $d,$e, $r,$rcomp
MOV $d,$d,LSR $r
ORR $d,$d,$e,LSL $rcomp
MEND
MACRO
ShiftL $d,$e, $r,$rcomp
MOV $e,$e,LSL $rcomp
ORR $e,$e,$d,LSR $r
MEND
MACRO
BitLOffset $b,$x, $xshftfactor,$npix,$log2bpc
AND $b,$x,$npix
MOV $b,$b,LSL $log2bpc
MEND
MACRO
BitROffset $b,$x, $xshftfactor,$npix,$log2bpc
AND $b,$x,$npix
ADD $b,$b,#1
MOV $b,$b,LSL $log2bpc
SUB $b,$b,#1
MEND
MACRO
WordOffset $w,$x, $xshftfactor,$npix,$log2bpc
MOV $w,$x,ASR $xshftfactor
MEND
MACRO
OffsetWordAndBit $o,$b,$x,$tmp
LDR $tmp,[WsPtr,#XShftFactor]
MOV $o,$x,ASR $tmp ;Word offset into scanline
LDR $tmp,[WsPtr,#NPix]
AND $b,$x,$tmp ;Pixel offset into word
LDR $tmp,[WsPtr,#Log2BPC]
MOV $b,$b,LSL $tmp ;Bit offset into word
MEND
MACRO
$label ErrorMsg $num,$string
$label DCD $num
DCB "$string", 0
ALIGN
MEND
;
; Macro when given a register will return the state to indicate
; if we are in a graphics mode. Originally lots of code used to simply
; load NPix and look for a null parameter (fair enough in 1-8 bit per pixel)
; but now we look at the mode flags, the choice of a new generation!
;
MACRO
$label GraphicsMode $scrap
$label LDR $scrap, [WsPtr, #ModeFlags]
TST $scrap, #ModeFlag_NonGraphic ;NE then non-graphic mode!
MEND
END