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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/compile-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/compile-bytecode.scm')
-rw-r--r--module/language/assembly/compile-bytecode.scm14
1 files changed, 8 insertions, 6 deletions
diff --git a/module/language/assembly/compile-bytecode.scm b/module/language/assembly/compile-bytecode.scm
index e8bba9e7e..5a8098112 100644
--- a/module/language/assembly/compile-bytecode.scm
+++ b/module/language/assembly/compile-bytecode.scm
@@ -55,6 +55,10 @@
(define (write-uint16-le x)
(write-byte (logand x 255))
(write-byte (logand (ash x -8) 255)))
+ (define (write-uint24-be x)
+ (write-byte (logand (ash x -16) 255))
+ (write-byte (logand (ash x -8) 255))
+ (write-byte (logand x 255)))
(define (write-uint32-be x)
(write-byte (logand (ash x -24) 255))
(write-byte (logand (ash x -16) 255))
@@ -85,12 +89,10 @@
;; Ew!
(for-each write-byte (bytevector->u8-list bv)))
(define (write-break label)
- (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 ((offset (- (assq-ref labels label) (+ (get-addr) 3))))
+ (cond ((>= offset (ash 1 23)) (error "jump too far forward" offset))
+ ((< offset (- (ash 1 23))) (error "jump too far backwards" offset))
+ (else (write-uint24-be offset)))))
(let ((inst (car asm))
(args (cdr asm))