68000: switch syscall API to register based

diff --git a/Kernel/lowlevel-68000.S b/Kernel/lowlevel-68000.S
index 1df9670..a29b961 100644 (file)
--- a/Kernel/lowlevel-68000.S
+++ b/Kernel/lowlevel-68000.S
@@ -476,21 +476,21 @@ trap15:           move.w #SIGTRAP,trap_id                 ; by convention
 
 ;
 ;              Save as little as we can
-;              a0/a1 we are allowed to trash
-;              d0/d1 are our returns
+;              on entry d0 = syscall, d1 = arg1 a0=arg2 a1=arg3 a2 = arg4
+;              d0/d1 are our returns and we trash a0/a1 (a2 will be
+;              preserved not that it matters much)
 ;              a5 we save, but otherwise we leave it to C to do needed
 ;              saves only
 ;
-trap14:                move.l a5,-(sp)
+;              fork is special see the fork code.
+;
+trap14:                move.l a5,-(sp)         ; must be first to match fork
+               move.l usp,a5
+               move.l a5,U_DATA__U_SYSCALL_SP(a5)
                move.l udata_shadow,a5
                move.b d0,U_DATA__U_CALLNO(a5)
-               move.l usp,a0
-               move.l a0,U_DATA__U_SYSCALL_SP(a5)
                move.b #1,U_DATA__U_INSYS(a5)
-               move.l 4(a0),U_DATA__U_ARGN(a5)
-               move.l 8(a0),U_DATA__U_ARGN1(a5)
-               move.l 12(a0),U_DATA__U_ARGN2(a5)
-               move.l 16(a0),U_DATA__U_ARGN3(a5)
+               movem.l d1/a0-a2,U_DATA__U_ARGN(a5)
                move.b #1,d0
                move.b d0,kernel_flag
                ; FIXME: EI per platform really