first of all, sorry if this is already discussed before..
this is C version:
/* BTST.L Dn,Dn */
unsigned long REGPARAM2 CPUFUNC(op_0100_0)(uae_u32 opcode, struct regstruct *regs)
{
uae_u32 srcreg = ((opcode >> 9) & 7);
uae_u32 dstreg = opcode & 7;
{{ uae_s32 src = m68k_dreg (regs, srcreg);
{...