The x=0 value comes from this hunk of code in vm-engine.c:
/* call-scm<-scm-uimm dst:8 a:8 b:8 IDX:32
*
* Call the SCM-returning instrinsic with index IDX, passing the SCM
* local A and the uint8_t immediate B as arguments. Place the SCM
* result in DST.
*/
VM_DEFINE_OP (53, call_scm_from_scm_uimm, "call-scm<-scm-uimm", DOP2 (X8_S8_S8
_C8, C32))
{
uint8_t dst, a, b;
SCM res;
scm_t_scm_from_scm_uimm_intrinsic intrinsic;
UNPACK_8_8_8 (op, dst, a, b);
intrinsic = intrinsics[ip[1]];
SYNC_IP ();
res = intrinsic (SP_REF (a), b);
CACHE_SP ();
SP_SET (dst, res);
NEXT (2);
}
SP_REF (a) evaluates to 0.
Regards,
Dave
--
John David Anglin dave.ang...@bell.net
