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authorAndy Wingo <wingo@pobox.com>2009-07-26 14:01:56 +0200
committerAndy Wingo <wingo@pobox.com>2009-07-26 14:01:56 +0200
commite5dc27b86d0eaa470f92cdaa9f4ed2a961338c49 (patch)
treec8c46f9c5995fd22c42f072faefacd7d075193fb /libguile/vm-i-system.c
parent28b119ee3da0f4b14cb87e638794d22843778cda (diff)
downloadguile-e5dc27b86d0eaa470f92cdaa9f4ed2a961338c49.tar.gz
increase range of relative jumps by aligning blocks to 8-byte boundaries
* libguile/objcodes.c (OBJCODE_COOKIE): Bump again, as our jump offsets are now multiplied by 8. * libguile/vm-i-system.c (BR): Interpret the 16-bit offset as a relative jump to the nearest 8-byte-aligned block -- increasing relative jump range from +/-32K to +/-240K. (mvra): Do the same for the mvra jump. * libguile/vm.c (really_make_boot_program): Align the mvra. * module/language/assembly.scm (align-block): New export, for aligning blocks. * module/language/assembly/compile-bytecode.scm (write-bytecode): Emit jumps to the nearest 8-byte-aligned block. Effectively our range is 18 bits in either direction. I would like to do this differently -- have long-br and long-br-if, and all the other br instructions go to 8 bits only. But the assembler doesn't have an appropriate representation to allow me to do this yet, so for now this is what we have. * module/language/assembly/decompile-bytecode.scm (decode-load-program): Decode the 19-bit jumps.
Diffstat (limited to 'libguile/vm-i-system.c')
-rw-r--r--libguile/vm-i-system.c20
1 files changed, 11 insertions, 9 deletions
diff --git a/libguile/vm-i-system.c b/libguile/vm-i-system.c
index b2cdca5be..726112c8a 100644
--- a/libguile/vm-i-system.c
+++ b/libguile/vm-i-system.c
@@ -426,7 +426,7 @@ VM_DEFINE_INSTRUCTION (34, long_toplevel_set, "long-toplevel-set", 2, 1, 0)
* branch and jump
*/
-/* offset must be a signed short!!! */
+/* offset must be a signed 16 bit int!!! */
#define FETCH_OFFSET(offset) \
{ \
int h = FETCH (); \
@@ -436,10 +436,10 @@ VM_DEFINE_INSTRUCTION (34, long_toplevel_set, "long-toplevel-set", 2, 1, 0)
#define BR(p) \
{ \
- signed short offset; \
+ scm_t_int16 offset; \
FETCH_OFFSET (offset); \
if (p) \
- ip += offset; \
+ ip += ((scm_t_ptrdiff)offset) * 8 - (((unsigned long)ip) % 8); \
NULLSTACK (1); \
DROP (); \
NEXT; \
@@ -447,9 +447,9 @@ VM_DEFINE_INSTRUCTION (34, long_toplevel_set, "long-toplevel-set", 2, 1, 0)
VM_DEFINE_INSTRUCTION (35, br, "br", 2, 0, 0)
{
- int h = FETCH ();
- int l = FETCH ();
- ip += (signed short) (h << 8) + l;
+ scm_t_int16 offset;
+ FETCH_OFFSET (offset);
+ ip += ((scm_t_ptrdiff)offset) * 8 - (((unsigned long)ip) % 8);
NEXT;
}
@@ -812,10 +812,12 @@ VM_DEFINE_INSTRUCTION (46, call_nargs, "call/nargs", 0, 0, 1)
VM_DEFINE_INSTRUCTION (47, mv_call, "mv-call", 3, -1, 1)
{
SCM x;
- signed short offset;
+ scm_t_int16 offset;
+ scm_t_uint8 *mvra;
nargs = FETCH ();
FETCH_OFFSET (offset);
+ mvra = ip + ((scm_t_ptrdiff)offset) * 8 - ((unsigned long)ip) % 8;
x = sp[-nargs];
@@ -828,7 +830,7 @@ VM_DEFINE_INSTRUCTION (47, mv_call, "mv-call", 3, -1, 1)
CACHE_PROGRAM ();
INIT_ARGS ();
NEW_FRAME ();
- SCM_FRAME_DATA_ADDRESS (fp)[1] = (SCM)(SCM_FRAME_RETURN_ADDRESS (fp) + offset);
+ SCM_FRAME_DATA_ADDRESS (fp)[1] = (SCM)mvra;
ENTER_HOOK ();
APPLY_HOOK ();
NEXT;
@@ -853,7 +855,7 @@ VM_DEFINE_INSTRUCTION (47, mv_call, "mv-call", 3, -1, 1)
len = scm_length (values);
PUSH_LIST (values, SCM_NULLP);
PUSH (len);
- ip += offset;
+ ip = mvra;
}
NEXT;
}