refact: make GetScrnAddr to use back buffer

Also makes SET_PIXEL_ADDR_ATTR to use ATTR buffer too.

Author: boriel

src/arch/zx48k/library-asm/SP/GetScrnAddr.asm

@@ -3,27 +3,24 @@
 ; Alvin Albrecht 2002
 ;
 
-;INCLUDE "SPconfig.def"
-;XLIB SPGetScrnAddr
-
 ; Get Screen Address
 ;
 ; Computes the screen address given a valid pixel coordinate.
 ; (0,0) is located at the top left corner of the screen.
 ;
-; enter: a = h = y coord
+; enter: h = y coord
 ;        l = x coord
 ;        In hi-res mode, Carry is most significant bit of x coord (0..511 pixels)
 ; exit : de = screen address, b = pixel mask
 ; uses : af, b, de, hl
 
-;IF !DISP_HIRES
-
     push namespace core
+    PROC
+    LOCAL rotloop, norotate
 
 SPGetScrnAddr:
+    ld a,h
     and $07
-    or $40
     ld d,a
     ld a,h
     rra
@@ -54,57 +51,12 @@ norotate:
     and $e0
     or l
     ld e,a
+    ld hl, (SCREEN_ADDR)
+    add hl, de
+    ex de, hl
     ret
 
+    ENDP
     pop namespace
 
-
-;ELSE
-;
-;.SPGetScrnAddr
-;   ld b,0
-;   ld d,b
-;   rr l
-;   rl b
-;   srl l
-;   rl b
-;   srl l
-;   rl b
-;   srl l
-;   jr nc, notodd
-;   ld d,$20
-;
-;.notodd
-;   ld a,b
-;  or a
-;   ld a,$80
-;  jr z, norotate
-;
-;.rotloop
-;   rra
-;   djnz rotloop
-
-;.norotate
-;   ld b,a
-;   ld a,h
-;   and $07
-;   or $40
-;   or d
-;   ld d,a
-;   ld a,h
-;   rra
-;   rra
-;   rra
-;   and $18
-;   or d
-;   ld d,a
-;
-;   ld a,h
-;   rla
-;   rla
-;   and $e0
-    ;  or l
-;   ld e,a
-;   ret
-
-;ENDIF
+#include once <sysvars.asm>

src/arch/zx48k/library-asm/set_pixel_addr_attr.asm

@@ -6,13 +6,16 @@ push namespace core
 ; HL contains the address in RAM for a given pixel (not a coordinate)
 SET_PIXEL_ADDR_ATTR:
     ;; gets ATTR position with offset given in SCREEN_ADDR
+    ld de, (SCREEN_ADDR)
+    or a
+    sbc hl, de
     ld a, h
     rrca
     rrca
     rrca
     and 3
-
     ld h, a
+
     ld de, (SCREEN_ATTR_ADDR)
     add hl, de  ;; Final screen addr
     jp __SET_ATTR2

src/arch/zx48k/library/SP/Fill.bas

@@ -112,7 +112,6 @@ SPPFill:
    dec bc			; we will start with one struct in the queue
    push bc			; save max stack depth variable
 
-   ld a,h
    call SPGetScrnAddr	; de = screen address, b = pixel byte
    ex de,hl			; hl = screen address
 

src/arch/zxnext/library-asm/SP/GetScrnAddr.asm

@@ -11,7 +11,7 @@
 ; Computes the screen address given a valid pixel coordinate.
 ; (0,0) is located at the top left corner of the screen.
 ;
-; enter: a = h = y coord
+; enter: h = y coord
 ;        l = x coord
 ;        In hi-res mode, Carry is most significant bit of x coord (0..511 pixels)
 ; exit : de = screen address, b = pixel mask
@@ -22,6 +22,7 @@
     push namespace core
 
 SPGetScrnAddr:
+    ld a,h
     and $07
     or $40
     ld d,a

src/arch/zxnext/library/SP/Fill.bas

@@ -112,15 +112,9 @@ SPPFill:
    dec bc			; we will start with one struct in the queue
    push bc			; save max stack depth variable
 
-   ld a,h
    call SPGetScrnAddr	; de = screen address, b = pixel byte
    ex de,hl			; hl = screen address
 
-;    ld b, h
-;    ld c, l
-;    call 22B0h      ; Uses ROM Pixel ADDR
-;    ld b, a
-
    call bytefill	; b = fill byte
    jr c, viable
    pop bc