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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
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.
-rw-r--r--libguile/_scm.h2
-rw-r--r--libguile/vm-i-system.c37
-rw-r--r--libguile/vm.c5
-rw-r--r--module/language/assembly.scm2
-rw-r--r--module/language/assembly/compile-bytecode.scm14
-rw-r--r--module/language/assembly/decompile-bytecode.scm19
6 files changed, 40 insertions, 39 deletions
diff --git a/libguile/_scm.h b/libguile/_scm.h
index 8a9a21161..6aedebe72 100644
--- a/libguile/_scm.h
+++ b/libguile/_scm.h
@@ -172,7 +172,7 @@
/* Major and minor versions must be single characters. */
#define SCM_OBJCODE_MAJOR_VERSION 0
-#define SCM_OBJCODE_MINOR_VERSION D
+#define SCM_OBJCODE_MINOR_VERSION E
#define SCM_OBJCODE_MAJOR_VERSION_STRING \
SCM_CPP_STRINGIFY(SCM_OBJCODE_MAJOR_VERSION)
#define SCM_OBJCODE_MINOR_VERSION_STRING \
diff --git a/libguile/vm-i-system.c b/libguile/vm-i-system.c
index 0662f8188..ac237e5b5 100644
--- a/libguile/vm-i-system.c
+++ b/libguile/vm-i-system.c
@@ -411,61 +411,62 @@ VM_DEFINE_INSTRUCTION (30, long_toplevel_set, "long-toplevel-set", 2, 1, 0)
* branch and jump
*/
-/* offset must be a signed 16 bit int!!! */
+/* offset must be at least 24 bits wide, and signed */
#define FETCH_OFFSET(offset) \
{ \
- int h = FETCH (); \
- int l = FETCH (); \
- offset = (h << 8) + l; \
+ offset = FETCH () << 16; \
+ offset += FETCH () << 8; \
+ offset += FETCH (); \
+ offset -= (offset & (1<<23)) << 1; \
}
#define BR(p) \
{ \
- scm_t_int16 offset; \
+ scm_t_int32 offset; \
FETCH_OFFSET (offset); \
if (p) \
- ip += ((scm_t_ptrdiff)offset) * 8 - (((unsigned long)ip) % 8); \
+ ip += offset; \
NULLSTACK (1); \
DROP (); \
NEXT; \
}
-VM_DEFINE_INSTRUCTION (31, br, "br", 2, 0, 0)
+VM_DEFINE_INSTRUCTION (31, br, "br", 3, 0, 0)
{
- scm_t_int16 offset;
+ scm_t_int32 offset;
FETCH_OFFSET (offset);
- ip += ((scm_t_ptrdiff)offset) * 8 - (((unsigned long)ip) % 8);
+ ip += offset;
NEXT;
}
-VM_DEFINE_INSTRUCTION (32, br_if, "br-if", 2, 0, 0)
+VM_DEFINE_INSTRUCTION (32, br_if, "br-if", 3, 0, 0)
{
BR (!SCM_FALSEP (*sp));
}
-VM_DEFINE_INSTRUCTION (33, br_if_not, "br-if-not", 2, 0, 0)
+VM_DEFINE_INSTRUCTION (33, br_if_not, "br-if-not", 3, 0, 0)
{
BR (SCM_FALSEP (*sp));
}
-VM_DEFINE_INSTRUCTION (34, br_if_eq, "br-if-eq", 2, 0, 0)
+VM_DEFINE_INSTRUCTION (34, br_if_eq, "br-if-eq", 3, 0, 0)
{
sp--; /* underflow? */
BR (SCM_EQ_P (sp[0], sp[1]));
}
-VM_DEFINE_INSTRUCTION (35, br_if_not_eq, "br-if-not-eq", 2, 0, 0)
+VM_DEFINE_INSTRUCTION (35, br_if_not_eq, "br-if-not-eq", 3, 0, 0)
{
sp--; /* underflow? */
BR (!SCM_EQ_P (sp[0], sp[1]));
}
-VM_DEFINE_INSTRUCTION (36, br_if_null, "br-if-null", 2, 0, 0)
+VM_DEFINE_INSTRUCTION (36, br_if_null, "br-if-null", 3, 0, 0)
{
BR (SCM_NULLP (*sp));
}
-VM_DEFINE_INSTRUCTION (37, br_if_not_null, "br-if-not-null", 2, 0, 0)
+VM_DEFINE_INSTRUCTION (37, br_if_not_null, "br-if-not-null", 3, 0, 0)
{
BR (!SCM_NULLP (*sp));
}
@@ -642,15 +643,15 @@ VM_DEFINE_INSTRUCTION (42, call_nargs, "call/nargs", 0, 0, 1)
goto vm_call;
}
-VM_DEFINE_INSTRUCTION (43, mv_call, "mv-call", 3, -1, 1)
+VM_DEFINE_INSTRUCTION (43, mv_call, "mv-call", 4, -1, 1)
{
SCM x;
- scm_t_int16 offset;
+ scm_t_int32 offset;
scm_t_uint8 *mvra;
nargs = FETCH ();
FETCH_OFFSET (offset);
- mvra = ip + ((scm_t_ptrdiff)offset) * 8 - ((unsigned long)ip) % 8;
+ mvra = ip + offset;
x = sp[-nargs];
diff --git a/libguile/vm.c b/libguile/vm.c
index d41c8cd41..cd730511f 100644
--- a/libguile/vm.c
+++ b/libguile/vm.c
@@ -180,9 +180,8 @@ static SCM
really_make_boot_program (long nargs)
{
SCM u8vec;
- scm_t_uint8 text[] = { scm_op_mv_call, 0, 0, 1,
- scm_op_make_int8_1, scm_op_nop, scm_op_nop, scm_op_nop,
- scm_op_halt };
+ scm_t_uint8 text[] = { scm_op_mv_call, 0, 0, 0, 1,
+ scm_op_make_int8_1, scm_op_halt };
struct scm_objcode *bp;
SCM ret;
diff --git a/module/language/assembly.scm b/module/language/assembly.scm
index 683da6cc1..2b22fd834 100644
--- a/module/language/assembly.scm
+++ b/module/language/assembly.scm
@@ -72,7 +72,7 @@
'(nop)))
(define (align-block addr)
- (code-alignment addr *block-alignment* 0))
+ '())
(define (align-code code addr alignment header-len)
`(,@(code-alignment addr alignment header-len)
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))
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))))))))))