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Amiga Assembly Library v41.21 — Motorola 68020 shared library for Commodore Amiga

DrawBox

Synopsis

DrawBox(rp, left, top, width, height) A1 D0 D1 D2 D3

C Prototype

void DrawBox(struct RastPort *rp, LONG left, LONG top, LONG width, LONG height);

Description

Draws a rectangle outline on a RastPort in an extremely fast manner. Particularly useful for C programmers.

Inputs

  • rp — Address of a RastPort structure.
  • left — X coordinate of the upper-left corner.
  • top — Y coordinate of the upper-left corner.
  • width — Width of the rectangle.
  • height — Height of the rectangle.

Result

None.

See Also

  • graphics.library/Draw()

Implementation

The original 68020 assembly implementation:

; (15-11-1994) --- DrawBox(rp, left, top, width, height) (a1,d0,d1,d2,d3) _LVODrawBox movem.l d2-d5/a2/a6,-(sp) move.l ab_GfxBase(a6),a6 move.w d0,d4 move.w d1,d5 move.l a1,a2 AMOVE a1 move.w d4,d0 move.w d5,d1 add.w d2,d0 jsr _LVODraw(a6) move.w d4,d0 move.w d5,d1 add.w d2,d0 add.w d3,d1 move.l a2,a1 jsr _LVODraw(a6) move.w d4,d0 move.w d5,d1 add.w d3,d1 move.l a2,a1 jsr _LVODraw(a6) move.w d4,d0 move.w d5,d1 move.l a2,a1 jsr _LVODraw(a6) movem.l (sp)+,d2-d5/a2/a6 rts
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