Exercise 5.35 · 习题

Exercise 5.35: What expression was compiled to
produce the code shown in Figure 5.18?

Figure 5.18: ↓ An example of compiler output. See
Exercise 5.35.

(assign val (op make-compiled-procedure)

(label entry16)

(reg env))

(goto (label after-lambda15))

entry16

(assign env (op compiled-procedure-env)

(reg proc))

(assign env (op extend-environment)

(const (x))

(reg argl)

(reg env))

(assign proc (op lookup-variable-value)

(const +)

(reg env))

(save continue) (save proc) (save env)

(assign proc (op lookup-variable-value)

(const g)

(reg env))

(save proc)

(assign proc (op lookup-variable-value)

(const +)

(reg env))

(assign val (const 2))

(assign argl (op list) (reg val))

(assign val (op lookup-variable-value)

(const x)

(reg env))

(assign argl (op cons)

(reg val)

(reg argl))

(test (op primitive-procedure?)

(reg proc))

(branch (label primitive-branch19))

compiled-branch18

(assign continue (label after-call17))

(assign val

(op compiled-procedure-entry)

(reg proc))

(goto (reg val))

primitive-branch19

(assign val

(op apply-primitive-procedure)

(reg proc)

(reg argl))

after-call17

(assign argl (op list) (reg val))

(restore proc)

(test (op primitive-procedure?)

(reg proc))

(branch (label primitive-branch22))

compiled-branch21

(assign continue (label after-call20))

(assign val

(op compiled-procedure-entry)

(reg proc))

(goto (reg val))

primitive-branch22

(assign val

(op apply-primitive-procedure)

(reg proc)

(reg argl))

after-call20

(assign argl (op list) (reg val))

(restore env)

(assign val

(op lookup-variable-value)

(const x)

(reg env))

(assign argl

(op cons)

(reg val)

(reg argl))

(restore proc)

(restore continue)

(test (op primitive-procedure?)

(reg proc))

(branch (label primitive-branch25))

compiled-branch24

(assign val (op compiled-procedure-entry)

(reg proc))

(goto (reg val))

primitive-branch25

(assign val

(op apply-primitive-procedure)

(reg proc)

(reg argl))

(goto (reg continue))

after-call23

after-lambda15

(perform (op define-variable!)

(const f)

(reg val)

(reg env))

(assign val (const ok))

练习 5.35：图 5.18 所示的代码是由哪个表达式编译而来的？

图 5.18：↓ 编译器输出示例。参见练习 5.35。

(assign val (op make-compiled-procedure)
(label entry16)
(reg env))
(goto (label after-lambda15))
entry16
(assign env (op compiled-procedure-env)
(reg proc))
(assign env (op extend-environment)
(const (x))
(reg argl)
(reg env))
(assign proc (op lookup-variable-value)
(const +)
(reg env))
(save continue) (save proc) (save env)
(assign proc (op lookup-variable-value)
(const g)
(reg env))
(save proc)
(assign proc (op lookup-variable-value)
(const +)
(reg env))
(assign val (const 2))
(assign argl (op list) (reg val))
(assign val (op lookup-variable-value)
(const x)
(reg env))
(assign argl (op cons)
(reg val)
(reg argl))
(test (op primitive-procedure?)
(reg proc))
(branch (label primitive-branch19))
compiled-branch18
(assign continue (label after-call17))
(assign val
(op compiled-procedure-entry)
(reg proc))
(goto (reg val))
primitive-branch19
(assign val
(op apply-primitive-procedure)
(reg proc)
(reg argl))
after-call17
(assign argl (op list) (reg val))
(restore proc)
(test (op primitive-procedure?)
(reg proc))
(branch (label primitive-branch22))
compiled-branch21
(assign continue (label after-call20))
(assign val
(op compiled-procedure-entry)
(reg proc))
(goto (reg val))
primitive-branch22
(assign val
(op apply-primitive-procedure)
(reg proc)
(reg argl))
after-call20
(assign argl (op list) (reg val))
(restore env)
(assign val
(op lookup-variable-value)
(const x)
(reg env))
(assign argl
(op cons)
(reg val)
(reg argl))
(restore proc)
(restore continue)
(test (op primitive-procedure?)
(reg proc))
(branch (label primitive-branch25))
compiled-branch24
(assign val (op compiled-procedure-entry)
(reg proc))
(goto (reg val))
primitive-branch25
(assign val
(op apply-primitive-procedure)
(reg proc)
(reg argl))
(goto (reg continue))
after-call23
after-lambda15
(perform (op define-variable!)
(const f)
(reg val)
(reg env))
(assign val (const ok))