@program prog_code,prog_name

;****************************************************************************
; Hex editor by Noah Stein
; Version 1.1
; Released October 29, 1997
;****************************************************************************

prog_code:
 move.w   #1,-(a7)
 jsr      romlib[set_font]
 lea      2(a7),a7
 bsr      clrscr
 bra      scrollv1

scrollv:
 jsr      flib[idle_loop]     
 cmp.w    #344,d0             
 beq      vup                
 cmp.w    #338,d0
 beq      vdown
 cmp.w    #4440,d0
 beq      vbup
 cmp.w    #4434,d0
 beq      vbdown
 cmp.w    #268,d0
 beq      storebookmark
 cmp.w    #269,d0
 beq      jumpbookmark
 cmp.w    #13,d0
 beq      findc
 cmp.w    #264,d0
 beq      end
scrollv1:
 bsr      scrollvp
 bra      scrollv

scrollvp:
 movem    d0/d1/d2/d4/a0,-(a7)
 moveq    #15,d7
scrollv2:
 lea      position(PC),a0
 move.l   (a0),d0
 move.l   d7,d5
 moveq    #15,d1
 sub.l    d5,d1
 move.l   d1,d6
 mulu     #8,d6
 add.l    d6,d0
 moveq    #0,d2
 moveq    #4,d4
 jsr      hexlib[put_hex]
 move.l   d0,a0
 move.l   (a0),d0
 moveq    #6,d2
 moveq    #7,d4
 jsr      hexlib[put_hex]
 move.l   4(a0),d0
 moveq    #14,d2
 jsr      hexlib[put_hex]
 bsr      asciiview
 dbra     d7,scrollv2
 movem    (a7)+,d0/d1/d2/d4/a0
 rts

asciiview:
 movem    d0-d7/a0-a1,-(a7)
 moveq    #3,d7
 lea      ascii(PC),a1
 mulu     #8,d1
asciiview2:
 moveq    #3,d6
 sub.b    d7,d6
 mulu     #2,d6
 move.w   0(a0,d6.w),d0
 ror.w    #8,d0
 cmp.b    #$0,d0
 beq      dot1
asciiview3:
 rol.w    #8,d0
 cmp.b    #$0,d0
 beq      dot2
asciiview4:
 move.w   d0,0(a1,d6.w)
 dbra     d7,asciiview2
 move.w   #4,-(a7)
 pea      ascii(PC)
 move.w   d1,-(a7)
 move.w   #184,-(a7)
 jsr      romlib[puttext]
 lea      10(a7),a7
 movem    (a7)+,d0-d7/a0-a1
 rts

dot1:
 move.b   #46,d0
 bra      asciiview3

dot2:
 move.b   #46,d0
 bra      asciiview4

vup:
 lea      position(PC),a0
 add.l    #$80,(a0)
 bra      vupcheck

vbup:
 lea      position(PC),a0
 add.l    #$1000,(a0)
 bra      vupcheck

vupcheck:
 lea      position(PC),a0
 cmp.l    #$1FF80,(a0)
 bls      scrollv1
 lea      position(PC),a0
 move.l   #$1FF80,(a0)
 bra      scrollv1

vdown:
 lea      position(PC),a0
 sub.l    #$80,(a0)
 bra      vdowncheck

vbdown:
 lea      position(PC),a0
 sub.l    #$1000,(a0)
 bra      vdowncheck

vdowncheck:
 lea      position(PC),a0
 cmp.l    #$20000,(a0)
 bls      scrollv1
 lea      position(PC),a0
 move.l   #0,(a0)
 bra      scrollv1

storebookmark:
 lea      position(PC),a0
 lea      bookmark(PC),a1
 move.l   (a0),(a1)
 bra      scrollv1

jumpbookmark:
 lea      position(PC),a0
 lea      bookmark(PC),a1
 move.l   (a1),(a0)
 bra      scrollv1

findc:
 bsr      scrollvp
findc1:
 bsr      highlight
findc2:
 jsr      flib[idle_loop]
 cmp.w    #338,d0
 beq      cup
 cmp.w    #340,d0
 beq      cright
 cmp.w    #344,d0
 beq      cdown
 cmp.w    #337,d0
 beq      cleft
 cmp.w    #13,d0
 beq      edit
 cmp.w    #264,d0
 beq      prog_code
 bra      findc2
highlight:
 movem    d0/a0,-(a7)
 move.w   x(PC),a0
 move.w   y(PC),d0
 add.l    #6,a0
 add.l    #LCD_MEM,a0
 mulu     #240,d0
 add.l    d0,a0
 moveq    #7,d0
highlight1:
 not.w    (a0)
 add.l    #30,a0
 dbra     d0,highlight1
 movem    (a7)+,d0/a0
 rts

cup:
 bsr      highlight
 lea      y(PC),a0
 move.w   (a0),d0
 sub.w    #1,(a0)
 cmp.w    #15,(a0)
 bls      findc1
 move.w   #15,(a0)
 bra      findc1

cdown:
 bsr      highlight
 lea      y(PC),a0
 move.w   (a0),d0
 add.w    #1,(a0)
 cmp.w    #15,(a0)
 bls      findc1
 move.w   #0,(a0)
 bra      findc1

cleft:
 bsr      highlight
 lea      x(PC),a0
 move.w   (a0),d0
 sub.w    #2,(a0)
 cmp.w    #14,(a0)
 bls      findc1
 move.w   #14,(a0)
 bra      findc1

cright:
 bsr      highlight
 lea      x(PC),a0
 move.w   (a0),d0
 add.w    #2,(a0)
 cmp.w    #14,(a0)
 bls      findc1
 move.w   #0,(a0)
 bra      findc1

clrscr:
 movem    d0/a0,-(a7)
 move.l   #$3BF,d0
 move.l   #LCD_MEM,a0
clrscr2:
 move.l   #0,(a0)+
 dbra     d0,clrscr2
 movem    (a7)+,d0/a0
 rts

edit:
 clr.l    d6
 clr.l    d1
 move.w   x(PC),d6
 move.w   y(PC),d1
 divu     #2,d6
 mulu     #8,d1
 move.l   d6,d2
 andi.w   #$FFFE,d2
 move.l   position(PC),a0
 add.l    d2,a0
 add.l    d1,a0
 clr.l    d3
 move.w   (a0),d3
 cmp.w    d2,d6
 bhi      editodd
 asr.w    #8,d3
edit2:
 clr.l    d6
 move.b   d3,d6
 moveq    #1,d4
 move.l   a0,-(a7)
edit3:
 moveq    #6,d2
 add.w    x(PC),d2
 move.w   y(PC),d1
 move.l   d6,d0
 jsr      hexlib[put_hex]
 bsr      highlight
 jsr      flib[idle_loop]
 cmp.w    #338,d0
 beq      editup
 cmp.w    #344,d0
 beq      editdown
 cmp.l    #4434,d0
 beq      editbup
 cmp.l    #4440,d0
 beq      editbdown
 cmp.w    #13,d0
 beq      editenter
 cmp.w    #264,d0
 beq      editesc
 bra      edit3

editesc:
 lea      4(a7),a7
editup:
 add.b    #1,d6
 bra      edit3

editdown:
 sub.b    #1,d6
 bra      edit3

editbup:
 add.b    #16,d6
 bra      edit3

editbdown:
 sub.b    #16,d6
 bra      edit3

editenter:
 move.l   (a7)+,a0
 clr.l    d1
 clr.l    d2
 clr.l    d5
 add.l    #$40000,a0
 move.w   x(PC),d1
 divu     #2,d1
 move.w   (a0),d5
 move.w   d1,d2
 andi     #$FFFE,d2
 cmp.w    d2,d1
 bhi      enterodd
 asl.w    #8,d6
 andi     #$00FF,d5
 add.w    d6,d5
 move.w   d5,(a0)
 bra      findc

enterodd:
 andi     #$FF00,d5
 add.w    d6,d5
 move.w   d5,(a0)
 bra      findc

editodd:
 andi.w   #$00FF,d3
 bra      edit2

end:
 rts

position  ds.l 1
bookmark  ds.l 1
x         dc.w 0
y         dc.w 0
ascii     ds.b 10

prog_name:
 dc.b "Hex Editor by Noah Stein",0

 reloc_open
 add_library flib
 add_library romlib
 add_library hexlib
 reloc_close
 end