diff options
| -rw-r--r-- | atk16_schasm/macros.scm | 36 |
1 files changed, 20 insertions, 16 deletions
diff --git a/atk16_schasm/macros.scm b/atk16_schasm/macros.scm index d5343f3..1a32cd4 100644 --- a/atk16_schasm/macros.scm +++ b/atk16_schasm/macros.scm @@ -34,6 +34,23 @@ (sub lhs (u16 1)) (br flag-sign (label dest) set: set))))) +(define-syntax emit-inverted-test + ;; jump to dest if <lhs op rhs> is NOT true. + ;; as such the behaviour of this macro can be considered to + ;; be inverted. + ;; the reason for this is to allow having the true branch + ;; before the false branch in memory (arbitrary decision). + (syntax-rules () + ((_ lhs op rhs dest) + (cond + ((eq? '== op) (emit-test-eq lhs rhs dest #f)) + ((eq? '!= op) (emit-test-eq lhs rhs dest #t)) + ((eq? '< op) (emit-test-lt lhs rhs dest #f)) + ((eq? '>= op) (emit-test-lt lhs rhs dest #t)) + ((eq? '<= op) (emit-test-lte lhs rhs dest #f)) + ((eq? '> op) (emit-test-lte lhs rhs dest #t)) + (else (error "unsupported operator" op)))))) + (define-syntax %if-else (syntax-rules () ((_ pred tb fb) @@ -45,14 +62,7 @@ (sym-end (string->symbol (format "~A-end" n)))) (ld *macro-scratch-reg* lhs) - (cond - ((eq? '== op) (emit-test-eq *macro-scratch-reg* rhs sym-false #f)) - ((eq? '!= op) (emit-test-eq *macro-scratch-reg* rhs sym-false #t)) - ((eq? '< op) (emit-test-lt *macro-scratch-reg* rhs sym-false #f)) - ((eq? '>= op) (emit-test-lt *macro-scratch-reg* rhs sym-false #t)) - ((eq? '<= op) (emit-test-lte *macro-scratch-reg* rhs sym-false #f)) - ((eq? '> op) (emit-test-lte *macro-scratch-reg* rhs sym-false #t)) - (else (error "unsupported operator" op))) + (emit-inverted-test *macro-scratch-reg* op rhs sym-false) tb (ld PC (label sym-end)) @@ -70,14 +80,8 @@ (sym-end (string->symbol (format "~A-end" n)))) (ld *macro-scratch-reg* lhs) - (cond - ((eq? '== op) (emit-test-eq *macro-scratch-reg* rhs sym-end #f)) - ((eq? '!= op) (emit-test-eq *macro-scratch-reg* rhs sym-end #t)) - ((eq? '< op) (emit-test-lt *macro-scratch-reg* rhs sym-end #f)) - ((eq? '>= op) (emit-test-lt *macro-scratch-reg* rhs sym-end #t)) - ((eq? '<= op) (emit-test-lte *macro-scratch-reg* rhs sym-end #f)) - ((eq? '> op) (emit-test-lte *macro-scratch-reg* rhs sym-end #t)) - (else (error "unsupported operator" op))) + (emit-inverted-test *macro-scratch-reg* op rhs sym-end) tb (def-label sym-end))))) + |