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ditch the 8-bit compiled form of program parameters

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* libguile/vm-i-loader.c (load-program):
* module/system/vm/assemble.scm (dump-object!): There are cases in which
  we use the 16-bit representation for program params (nargs, nexts,
  etc), but the actual 16-bit number actually fits into 8 bits -- which
  is then misinterpreted by the loader as the 8-bit form. So ditch the
  8-bit form entirely (it was never much of an optimization), and just
  use the 16-bit form. Make sure to clear out all your .go files before
  recompiling this one!
This commit is contained in:
Andy Wingo 2008-09-02 10:23:05 -07:00
parent 7950b4cffb
commit 5c4926209f
2 changed files with 6 additions and 23 deletions
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25
libguile/vm-i-loader.c
View file

@ -141,25 +141,12 @@ VM_DEFINE_LOADER (load_program, "load-program")
/* NOTE: format defined in system/vm/assemble.scm */
if (SCM_I_INUMP (x))
{
int i = SCM_I_INUM (x);
if (-128 <= i && i <= 127)
{
scm_t_uint8 c = (scm_t_uint8)i;
/* 8-bit representation */
p->nargs = (c >> 6) & 0x03; /* 7-6 bits */
p->nrest = (c >> 5) & 0x01; /* 5 bit */
p->nlocs = (c >> 2) & 0x07; /* 4-2 bits */
p->nexts = c & 0x03; /* 1-0 bits */
}
else
{
scm_t_uint16 s = (scm_t_uint16)i;
/* 16-bit representation */
p->nargs = (s >> 12) & 0x0f; /* 15-12 bits */
p->nrest = (s >> 11) & 0x01; /* 11 bit */
p->nlocs = (s >> 4) & 0x7f; /* 10-04 bits */
p->nexts = s & 0x0f; /* 03-00 bits */
}
scm_t_uint16 s = (scm_t_uint16)SCM_I_INUM (x);
/* 16-bit representation */
p->nargs = (s >> 12) & 0x0f; /* 15-12 bits */
p->nrest = (s >> 11) & 0x01; /* 11 bit */
p->nlocs = (s >> 4) & 0x7f; /* 10-04 bits */
p->nexts = s & 0x0f; /* 03-00 bits */
}
else
{

4
module/system/vm/assemble.scm
View file

@ -250,10 +250,6 @@
(let ((nargs (glil-vars-nargs vars)) (nrest (glil-vars-nrest vars))
(nlocs (glil-vars-nlocs vars)) (nexts (glil-vars-nexts vars)))
(cond
((and (< nargs 4) (< nlocs 8) (< nexts 4))
;; 8-bit representation
(let ((x (+ (* nargs 64) (* nrest 32) (* nlocs 4) nexts)))
(push-code! `(make-int8 ,x))))
((and (< nargs 16) (< nlocs 128) (< nexts 16))
;; 16-bit representation
(let ((x (+ (* nargs 4096) (* nrest 2048) (* nlocs 16) nexts)))