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authorAndy Wingo <wingo@pobox.com>2009-09-17 14:58:31 +0200
committerAndy Wingo <wingo@pobox.com>2009-10-16 15:56:11 +0200
commit97fcf583b7239ea17dbb73eae9438d21136eb2db (patch)
treef92ae6b6b840255fe58289b9ed3824aac3cbd0c5 /module/language/assembly/decompile-bytecode.scm
parentf95f82f8e183f2744740bdc950dba9c856e09094 (diff)
downloadguile-97fcf583b7239ea17dbb73eae9438d21136eb2db.tar.gz
jumps encoded using 24 bits, not 19; blocks no longer aligned
* libguile/_scm.h (SCM_OBJCODE_MINOR_VERSION): Bump. * libguile/vm-i-system.c (FETCH_OFFSET, BR): Labels are no longer 8-byte aligned; instead, jumps are encoded into 3 bytes instead of 2. (br, br-if, br-if-not, br-if-eq, br-if-not-eq, br-if-null) (br-if-not-null, mv-call): Adapt for new length of br instructions (3 bytes instead of 2). * libguile/vm.c (really_make_boot_program): Adapt hand-coded bytecode for new offset regime. * module/language/assembly.scm (align-block): No alignment necessary. * module/language/assembly/compile-bytecode.scm (write-bytecode): Write out breaks as 24-bit relative jumps. * module/language/assembly/decompile-bytecode.scm (decode-load-program): Decompile break instructions.
Diffstat (limited to 'module/language/assembly/decompile-bytecode.scm')
-rw-r--r--module/language/assembly/decompile-bytecode.scm19
1 files changed, 9 insertions, 10 deletions
diff --git a/module/language/assembly/decompile-bytecode.scm b/module/language/assembly/decompile-bytecode.scm
index 511c6ccc6..915e101b8 100644
--- a/module/language/assembly/decompile-bytecode.scm
+++ b/module/language/assembly/decompile-bytecode.scm
@@ -43,11 +43,11 @@
(define (br-instruction? x)
(memq x '(br br-if br-if-not br-if-eq br-if-not-eq br-if-null br-if-not-null)))
-(define (bytes->s16 a b)
- (let ((x (+ (ash a 8) b)))
- (if (zero? (logand (ash 1 15) x))
+(define (bytes->s24 a b c)
+ (let ((x (+ (ash a 16) (ash b 8) c)))
+ (if (zero? (logand (ash 1 23) x))
x
- (- x (ash 1 16)))))
+ (- x (ash 1 24)))))
;; FIXME: this is a little-endian disassembly!!!
(define (decode-load-program pop)
@@ -60,9 +60,8 @@
(%unused-pad (begin (pop) (pop) (pop) (pop)))
(labels '())
(i 0))
- (define (ensure-label rel1 rel2)
- (let ((where (+ (logand i (lognot #x7))
- (* (bytes->s16 rel1 rel2) 8))))
+ (define (ensure-label rel1 rel2 rel3)
+ (let ((where (+ i (bytes->s24 rel1 rel2 rel3))))
(or (assv-ref labels where)
(begin
(let ((l (gensym ":L")))
@@ -87,9 +86,9 @@
(else
(let ((exp (decode-bytecode sub-pop)))
(pmatch exp
- ((,br ,rel1 ,rel2) (guard (br-instruction? br))
- (lp (cons `(,br ,(ensure-label rel1 rel2)) out)))
- ((mv-call ,n ,rel1 ,rel2)
+ ((,br ,rel1 ,rel2 ,rel3) (guard (br-instruction? br))
+ (lp (cons `(,br ,(ensure-label rel1 rel2 rel3)) out)))
+ ((mv-call ,n ,rel1 ,rel2 ,rel3)
(lp (cons `(mv-call ,n ,(ensure-label rel1 rel2)) out)))
(else
(lp (cons exp out))))))))))