66 lines
2.3 KiB
Racket
66 lines
2.3 KiB
Racket
#lang racket
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(require racket/list)
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(provide select-instructions)
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(define (select-instructions p)
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(match p
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[`(program ,data ,body) `(AArch64VProgram ,data ,(select-instructions-section (car body)))]))
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(define (select-instructions-section sec)
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(match sec
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[`(,label . ,statement) `(,label . (Block `() ,(select-instructions-stmt statement)))]))
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(define (select-instructions-stmt stmt)
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(match stmt
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[`(return ,exp) (select-instructions-return exp)]
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[`(seq (assign ,var ,exp) ,next-stmt)
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(append (select-instructions-assign var exp)
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(select-instructions-stmt next-stmt))]))
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(define (select-instructions-assign var exp)
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(match exp
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[(? symbol?) (list `(Instr mov ((Var ,var) (Var ,exp))))]
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[(? fixnum?) (list `(Instr mov ((Var ,var) (Imm ,exp))))]
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[`(read) (select-instructions-read `(Var ,var))]
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[`(- ,e) (select-instructions-neg e `(Var ,var))]
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[`(+ ,a ,b) (select-instructions-add a b `(Var ,var))]))
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(define (select-instructions-return exp)
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(append (match exp
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[(? symbol?) (list `(Instr mov (x0 (Var ,exp))))]
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[(? fixnum?) (list `(Instr mov (x0 (Imm ,exp))))]
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[`(read) (select-instructions-read 'x0)]
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[`(- ,e) (select-instructions-neg e 'x0)]
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[`(+ ,a ,b) (select-instructions-add a b 'x0)])
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`[(Instr b (conclusion))]))
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(define (select-instructions-read dest)
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(if (eq? dest 'x0)
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(list `(Instr bl _builtin_read))
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(list `(Instr bl _builtin_read) `(Instr mov (,dest x0)))))
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(define (select-instructions-neg exp dest)
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(begin
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(define var-exp (if (fixnum? exp)
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`(Imm ,exp)
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`(Var ,exp)))
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(list `(Instr neg (,dest ,var-exp)))))
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(define (select-instructions-add a b dest)
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(begin
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; if e1 is an imm, swap
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(define-values (e1 e2) (imm-to-right a b))
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(define num-imm (count fixnum? (list e1 e2)))
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(match num-imm
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[0 (list `(Instr add (,dest (Var ,e1) (Var ,e2))))]
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[1 (list `(Instr add (,dest (Var ,e1) (Imm ,e2))))]
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[2 (list `(Instr mov (,dest (Imm ,e1)))
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`(Instr add (,dest ,dest (Imm ,e2))))])))
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(define (imm-to-right e1 e2)
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(if (and (fixnum? e1) (not (fixnum? e2)))
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(values e2 e1)
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(values e1 e2)))
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