[A83] Re: Grey scale(and sprite doodling)

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[A83] Re: Grey scale(and sprite doodling)


Ok, I'm trying to get the sprite clipping routine to work with this(i'm 
editing the and/xor one cause that one would be an 'easier' fix.  But I can't 
get it to work, any ideas?  my code(gives me an Err:Domain error, probably 
not poping correctly or something):
PutSprClp:      XOR  A
__Change_1:     LD   DE, DefaultSpriteHeight      ; D = 0, E = Height

                OR   C                            ; If C < 0
                JP   M, _PSC_NoBotClp             ; No bottom clip.

                LD   A, $3F                       ; Is C is offscreen?
                SUB  C
                RET  C

__Change_2:     CP   DefaultSpriteHeight-1        ; If C + 7 < 64
                JR   NC, _PSC_NoVertClp           ; No vertical clip.
                INC  A
                LD   E, A
                JR   _PSC_NoVertClp               ; Height = 64 - C

_PSC_NoBotClp:
__Change_3:     CP   -(DefaultSpriteHeight-1)     ; Is C is offscreen?
                RET  C

                ADD  A, E                         ; Find how many lines
                LD   C, A                         ; to actually draw
                SUB  E

                NEG
                LD   E, A
                ADD  HL, DE                       ; Move HL down
                LD   E, C                         ; by -C lines
                LD   C, D

_PSC_NoVertClp: PUSH HL                           ; IX -> Sprite
                POP  IX

                LD   A, $77                       ; OP code for
                LD   (_PSC_OPchg_1), A            ;   LD   (HL), A
                LD   (_PSC_OPchg_2), A

                XOR  A                            ; Is B > 0?
                OR   B
                JP   M, _PSC_NoRightClp

                CP   89                           ; Is B < 89?
                JR   C, _PSC_ClpDone
                CP   96
                RET  NC

                LD   HL, _PSC_OPchg_1             ; Modify LD to NOP
                JR   _PSC_ClpModify

_PSC_NoRightClp:CP   -7                           ; Is B is offscreen?
                RET  C

                LD   HL, _PSC_OPchg_2             ; Modify LD to NOP
_PSC_ClpModify: LD   (HL), D

_PSC_ClpDone:   LD   B, E                         ; B = number of rows

                LD   H, A
                CPL
                AND  %00000111
                LD   (_PSC_OPchg_4 + 1), A
                XOR  %00000111
                LD   (_PSC_OPchg_3 + 1), A
                LD   E, A
                XOR  H
                LD   HL, MaskTable
                ADD  HL, DE
                LD   E, C
                LD   C, (HL)

                LD   H, D
                LD   L, E
                ADD  HL, DE                       ; HL = Y * 12
                ADD  HL, DE
                ADD  HL, HL
                ADD  HL, HL

                ADD  A, 8
                RRCA
                RRCA
                RRCA

                LD   E, A                         ; HL = Y*12 + X/8
                ADD  HL, DE

                LD   DE, GRAPH_MEM - 1
                ADD  HL, DE

        push hl
        ld   de, SafeRam1 -1
        add hl,de
        ex (sp),hl

                LD   A, C
                LD   (_PSC_OPchg_6 + 1), A        ; mask
                LD   (_PSC_OPchg_7 + 1), A        ; mask
                CPL
                LD   (_PSC_OPchg_8 + 1), A        ; mask

_PSC_LineLoop:
__Change_4:     LD   A, (IX+DefaultSpriteHeight)
_PSC_OPchg_3:   JR   _PSC_OPchg_3                 ; modify

                RLCA
                RLCA
                RLCA
                RLCA
                RLCA
                RLCA
                RLCA
                RLCA

                LD   E, A
_PSC_OPchg_6:   AND  %11110000
                LD   C, A
                XOR  E
                LD   D, A

                LD   A, (IX+0)
_PSC_OPchg_4:   JR   _PSC_OPchg_4                 ; modify

                RRCA
                RRCA
                RRCA
                RRCA
                RRCA
                RRCA
                RRCA

                LD   E, A
_PSC_OPchg_7:   OR   %11110000
                XOR  (HL)                         ; AND with background
        ld   (hl),a
        ex   (sp),hl
        ld   a,d
                XOR  (hl)                            ; XOR with background
_PSC_OPchg_2:   LD   (HL), A                      ; Write
        inc  hl
        ex   (sp),hl
                INC  HL                           ; HL -> next 8 pixels

                LD   A, E
_PSC_OPchg_8:   OR   %00001111
                Xor  (HL)                         ; AND with background
        ld (hl),a
        ex (sp),hl
        ld a,c
                XOR  (HL)                            ; XOR with background
_PSC_OPchg_1:   LD   (HL), A                      ; Write

                LD   DE, 11
                ADD  HL, DE                       ; HL -> next row

                INC  IX                           ; Increment to next data

                DJNZ _PSC_LineLoop
                RET

MaskTable:      .DB   %00000000
                .DB   %10000000
                .DB   %11000000
                .DB   %11100000
                .DB   %11110000
                .DB   %11111000
                .DB   %11111100
                .DB   %11111110
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