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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
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.
-rw-r--r--libguile/objcodes.c2
-rw-r--r--libguile/vm-i-system.c20
-rw-r--r--libguile/vm.c2
-rw-r--r--module/language/assembly.scm17
-rw-r--r--module/language/assembly/compile-bytecode.scm10
-rw-r--r--module/language/assembly/decompile-bytecode.scm3
-rw-r--r--module/language/glil/compile-assembly.scm11
7 files changed, 39 insertions, 26 deletions
diff --git a/libguile/objcodes.c b/libguile/objcodes.c
index 728dd8d13..91691a70a 100644
--- a/libguile/objcodes.c
+++ b/libguile/objcodes.c
@@ -50,7 +50,7 @@
/* The objcode magic header. */
#define OBJCODE_COOKIE \
- "GOOF-0.8-" OBJCODE_ENDIANNESS "-" OBJCODE_WORD_SIZE "---"
+ "GOOF-0.9-" OBJCODE_ENDIANNESS "-" OBJCODE_WORD_SIZE "---"
/* The length of the header must be a multiple of 8 bytes. */
verify (((sizeof (OBJCODE_COOKIE) - 1) & 7) == 0);
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;
}
diff --git a/libguile/vm.c b/libguile/vm.c
index 527598b86..cc5e4f924 100644
--- a/libguile/vm.c
+++ b/libguile/vm.c
@@ -226,7 +226,7 @@ really_make_boot_program (long nargs)
SCM u8vec;
/* Make sure "bytes" is 64-bit aligned. */
scm_t_uint8 text[] = { scm_op_mv_call, 0, 0, 1,
- scm_op_make_int8_1,
+ scm_op_make_int8_1, scm_op_nop, scm_op_nop, scm_op_nop,
scm_op_halt };
struct scm_objcode *bp;
SCM ret;
diff --git a/module/language/assembly.scm b/module/language/assembly.scm
index 90b2acc03..e7308ac6f 100644
--- a/module/language/assembly.scm
+++ b/module/language/assembly.scm
@@ -24,7 +24,7 @@
#:use-module (system vm instruction)
#:use-module ((srfi srfi-1) #:select (fold))
#:export (byte-length
- addr+ align-program align-code
+ addr+ align-program align-code align-block
assembly-pack assembly-unpack
object->assembly assembly->object))
@@ -63,17 +63,24 @@
(define *program-alignment* 8)
+(define *block-alignment* 8)
+
(define (addr+ addr code)
(fold (lambda (x len) (+ (byte-length x) len))
addr
code))
+(define (code-alignment addr alignment header-len)
+ (make-list (modulo (- alignment
+ (modulo (+ addr header-len) alignment))
+ alignment)
+ '(nop)))
+
+(define (align-block addr)
+ (code-alignment addr *block-alignment* 0))
(define (align-code code addr alignment header-len)
- `(,@(make-list (modulo (- alignment
- (modulo (+ addr header-len) alignment))
- alignment)
- '(nop))
+ `(,@(code-alignment addr alignment header-len)
,code))
(define (align-program prog addr)
diff --git a/module/language/assembly/compile-bytecode.scm b/module/language/assembly/compile-bytecode.scm
index 58afddde0..bf6c5f7b5 100644
--- a/module/language/assembly/compile-bytecode.scm
+++ b/module/language/assembly/compile-bytecode.scm
@@ -77,10 +77,12 @@
;; Ew!
(for-each write-byte (bytevector->u8-list bv)))
(define (write-break label)
- (let ((offset (- (assq-ref labels label) (+ (get-addr) 2))))
- (cond ((>= offset (ash 1 15)) (error "jump too big" offset))
- ((< offset (- (ash 1 15))) (error "reverse jump too big" offset))
- (else (write-uint16-be offset)))))
+ (let ((offset (- (assq-ref labels label)
+ (logand (+ (get-addr) 2) (lognot #x7)))))
+ (cond ((not (= 0 (modulo offset 8))) (error "unaligned jump" offset))
+ ((>= offset (ash 1 18)) (error "jump too far forward" offset))
+ ((< offset (- (ash 1 18))) (error "jump too far backwards" offset))
+ (else (write-uint16-be (ash offset -3))))))
(let ((inst (car asm))
(args (cdr asm))
diff --git a/module/language/assembly/decompile-bytecode.scm b/module/language/assembly/decompile-bytecode.scm
index 82459fc6f..0e34ab4a2 100644
--- a/module/language/assembly/decompile-bytecode.scm
+++ b/module/language/assembly/decompile-bytecode.scm
@@ -61,7 +61,8 @@
(labels '())
(i 0))
(define (ensure-label rel1 rel2)
- (let ((where (+ i (bytes->s16 rel1 rel2))))
+ (let ((where (+ (logand i (lognot #x7))
+ (* (bytes->s16 rel1 rel2) 8))))
(or (assv-ref labels where)
(begin
(let ((l (gensym ":L")))
diff --git a/module/language/glil/compile-assembly.scm b/module/language/glil/compile-assembly.scm
index 2e586ec5e..fa5805757 100644
--- a/module/language/glil/compile-assembly.scm
+++ b/module/language/glil/compile-assembly.scm
@@ -340,11 +340,12 @@
(error "unknown module var kind" op key)))))
((<glil-label> label)
- (values '()
- bindings
- source-alist
- (acons label addr label-alist)
- object-alist))
+ (let ((code (align-block addr)))
+ (values code
+ bindings
+ source-alist
+ (acons label (addr+ addr code) label-alist)
+ object-alist)))
((<glil-branch> inst label)
(emit-code `((,inst ,label))))