Pluggable instruction sets

scmvm/assembler.scm

@@ -9,24 +9,26 @@
 	    assembler-pos assembler-pos-set!
 	    assembler-buf
 	    assembler-labels
+            assembler-instruction-set
 	    emit-label
 	    emit-instruction
 	    emit-literal
 	    emit-reference
-	    finalize-references
+            assembler-backpatch!
 	    assembler-dump-program))
 
 (define (make-label) (cons #f '()))
 
 (define-record-type <assembler>
-  (make-assembler pos buf labels)
+  (make-assembler pos buf labels instruction-set)
   assembler?
   (pos assembler-pos assembler-pos-set!)
   (buf assembler-buf assembler-buf-set!)
-  (labels assembler-labels))
+  (labels assembler-labels)
+  (instruction-set assembler-instruction-set))
 
-(define (make-assembler*)
-  (make-assembler 0 (make-bytevector 1024) (make-hash-table)))
+(define (make-assembler* instruction-set)
+  (make-assembler 0 (make-bytevector 1024) (make-hash-table) instruction-set))
 
 (define (assembler-buf-grow! asm)
   (let ([buf (make-bytevector (ash (bytevector-length (assembler-buf asm)) -1))])
@@ -59,7 +61,7 @@
   (assembler-label-add-value asm name (assembler-pos asm)))
 
 (define (emit-instruction asm inst)
-  (let ([inst-object (assq inst *instruction-set*)])
+  (let ([inst-object (instruction-lookup (assembler-instruction-set asm) inst)])
     (write-byte (instruction-code inst-object) asm)
     (assembler-pos-set! asm (+ (assembler-pos asm) 1))))
 
@@ -71,7 +73,7 @@
   (assembler-label-add-reference asm name (assembler-pos asm))
   (assembler-pos-set! asm (+ (assembler-pos asm) 4)))
 
-(define (finalize-references asm)
+(define (assembler-backpatch! asm)
   (define (install-location _name label)
     (for-each
      (cute write-word (car label) asm <>)