bon c'est en asm mais en c j'en sais rien...
QuickClearScreen: ;a0=screen ptr+3840
movem.l d0-a7,QuickClearScreen_SvgrRegs
move.l a0,a7
moveq.l #0,d0
move.l d0,d1
move.l d0,d2
move.l d0,d3
move.l d0,d4
move.l d0,d5
move.l d0,d6
movea.l d0,a0
movea.l d0,a1
movea.l d0,a2
movea.l d0,a3
movea.l d0,a4
movea.l d0,a5
movea.l d0,a6
moveq.l #5,d7
QuickClearScreen_Loop:
movem.l d0-d6/a0-a6,-(a7)
movem.l d0-d6/a0-a6,-(a7)
movem.l d0-d6/a0-a6,-(a7)
movem.l d0-d6/a0-a6,-(a7)
movem.l d0-d6/a0-a6,-(a7)
movem.l d0-d6/a0-a6,-(a7)
movem.l d0-d6/a0-a6,-(a7)
movem.l d0-d6/a0-a6,-(a7)
movem.l d0-d6/a0-a6,-(a7)
movem.l d0-d6/a0-a6,-(a7)
movem.l d0-d6/a0-a6,-(a7)
dbf.s d7,QuickClearScreen_Loop
movem.l d0-d6/a0-a6,-(a7)
movem.l d0-d6/a0-a6,-(a7)
movem.l d0-d6/a0,-(a7)
movem.l QuickClearScreen_SvgrRegs(pc),d0-a7
rts
QuickClearScreen_SvgrRegs ds.l 16
et tu l'appelles comme ça:
lea screen_buffer+3840,a0
bsr QuickClearScreen