version 1.27, 1996/09/24 19:15:02
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version 1.28, 1996/09/30 13:16:10
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Line 448 forth definitions
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Line 448 forth definitions
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\ If this assumption is too optimistic, the compiler will warn the user. |
\ If this assumption is too optimistic, the compiler will warn the user. |
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\ Implementation: migrated to kernel.fs |
\ Implementation: |
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\ THEN (another control flow from before joins the current one): |
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\ The new locals-list is the intersection of the current locals-list and |
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\ the orig-local-list. The new locals-size is the (alignment-adjusted) |
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\ size of the new locals-list. The following code is generated: |
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\ lp+!# (current-locals-size - orig-locals-size) |
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\ <then>: |
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\ lp+!# (orig-locals-size - new-locals-size) |
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\ Of course "lp+!# 0" is not generated. Still this is admittedly a bit |
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\ inefficient, e.g. if there is a locals declaration between IF and |
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\ ELSE. However, if ELSE generates an appropriate "lp+!#" before the |
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\ branch, there will be none after the target <then>. |
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\ explicit scoping |
\ explicit scoping |
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Line 495 forth definitions
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Line 482 forth definitions
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lastcfa ! last ! |
lastcfa ! last ! |
DEFERS ;-hook ; |
DEFERS ;-hook ; |
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\ THEN (another control flow from before joins the current one): |
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\ The new locals-list is the intersection of the current locals-list and |
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\ the orig-local-list. The new locals-size is the (alignment-adjusted) |
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\ size of the new locals-list. The following code is generated: |
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\ lp+!# (current-locals-size - orig-locals-size) |
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\ <then>: |
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\ lp+!# (orig-locals-size - new-locals-size) |
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\ Of course "lp+!# 0" is not generated. Still this is admittedly a bit |
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\ inefficient, e.g. if there is a locals declaration between IF and |
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\ ELSE. However, if ELSE generates an appropriate "lp+!#" before the |
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\ branch, there will be none after the target <then>. |
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: (then-like) ( orig -- addr ) |
: (then-like) ( orig -- addr ) |
swap -rot dead-orig = |
swap -rot dead-orig = |
if |
if |
Line 570 forth definitions
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Line 570 forth definitions
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\ things above are not control flow joins. Everything should be taken |
\ things above are not control flow joins. Everything should be taken |
\ over from the live flow. No lp+!# is generated. |
\ over from the live flow. No lp+!# is generated. |
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\ !! The lp gymnastics for UNTIL are also a real problem: locals cannot be |
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\ used in signal handlers (or anything else that may be called while |
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\ locals live beyond the lp) without changing the locals stack. |
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\ About warning against uses of dead locals. There are several options: |
\ About warning against uses of dead locals. There are several options: |
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\ 1) Do not complain (After all, this is Forth;-) |
\ 1) Do not complain (After all, this is Forth;-) |
Line 643 forth definitions
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Line 639 forth definitions
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endif ; |
endif ; |
:noname |
:noname |
0 0 0. 0.0e0 { c: clocal w: wlocal d: dlocal f: flocal } |
0 0 0. 0.0e0 { c: clocal w: wlocal d: dlocal f: flocal } |
' dup >definer |
comp' drop dup >definer |
case |
case |
[ ' locals-wordlist >definer ] literal \ value |
[ ' locals-wordlist >definer ] literal \ value |
OF >body POSTPONE Aliteral POSTPONE ! ENDOF |
OF >body POSTPONE Aliteral POSTPONE ! ENDOF |