+ (addr+ ptr
+ (case mode
+ ((immediate) 0)
+ ((direct) num)
+ ((indirect-A) (addr+ num ((core-get (addr+ ptr num)) 'A-num)))
+ ((indirect-B) (addr+ num ((core-get (addr+ ptr num)) 'B-num)))
+ ((pre-indirect-A)
+ (let ((aux-instr (core-get (addr+ ptr num))))
+ (instr-set-A-num! aux-instr (addr+ -1 (aux-instr 'A-num)))
+ (addr+ num (aux-instr 'A-num))))
+ ((pre-indirect-B)
+ (let ((aux-instr (core-get (addr+ ptr num))))
+ (instr-set-B-num! aux-instr (addr+ -1 (aux-instr 'B-num)))
+ (addr+ num (aux-instr 'B-num))))
+ ((post-indirect-A)
+ (let* ((aux-instr (core-get (addr+ ptr num)))
+ (old-A-num (aux-instr 'A-num)))
+ (instr-set-A-num! aux-instr (addr+ 1 (aux-instr 'A-num)))
+ (addr+ num old-A-num)))
+ ((post-indirect-B)
+ (let* ((aux-instr (core-get (addr+ ptr num)))
+ (old-B-num (aux-instr 'B-num)))
+ (instr-set-B-num! aux-instr (addr+ 1 (aux-instr 'B-num)))
+ (addr+ num old-B-num)))
+ (else
+ (error "Unrecognized mode" mode)))))
+
+;;; TEST CODE
+
+(define addressing-test
+ (make-prog 'at (list
+ (make-instr 'DAT 'F 'immediate 42 'immediate 53 'at)
+ (make-instr 'DAT 'F 'immediate 123 'immediate 256 'at)
+ (make-instr 'MOV 'A 'indirect-B 4 'direct 7 'at)
+ (make-instr 'NOP 'I 'immediate 0 'immediate 0 'at)
+ (make-instr 'NOP 'I 'immediate 0 'immediate 0 'at)
+ (make-instr 'NOP 'I 'immediate 0 'immediate 0 'at)
+ (make-instr 'DAT 'F 'immediate -5 'immediate -6 'at)) 2))
+
+(define imp
+ (make-prog 'imp (list (make-instr 'MOV 'I 'direct 0 'direct 1 'imp)) 0))
+
+(define dwarf
+ (make-prog 'dwarf (list
+ (make-instr 'DAT 'F 'immediate 0 'immediate -1 'dwarf)
+ (make-instr 'ADD 'AB 'immediate 5 'direct -1 'dwarf)
+ (make-instr 'MOV 'I 'direct -2 'indirect-B -2 'dwarf)
+ (make-instr 'JMP 'I 'immediate -2 'immediate 0 'dwarf)) 1))
+
+(initialize-core)
+(define players (install-progs (list dwarf imp)))
+
+(dump-core)