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more clarifications and notes

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~d6 2024-08-02 13:41:33 -04:00
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@ -64,7 +64,11 @@ For example the generic effect for \fBADD\fP is ( x y -- x+y ). The eight combin
\fBADD2k\fP ( x* y* -- x* y* x+y* ) sum two shorts using \fBwst\fP, retain arguments
\fBADD2kr\fP ( [x* y*] -- [x* y* x+y*] ) sum two shorts using \fBrst\fP, retain arguments
Thus for regular instructions writing a "generic" effect (leaving sigils off values whose size depends on \fIshort\fP mode) is sufficient to describe its behavior across all eight variations. Note that some instructions always read values of a fixed size. (For example the boolean condition read by \fBJCN\fP is always one byte, no matter what modes are used.)
Thus for regular instructions writing a "generic" effect (leaving sigils off values whose size depends on \fIshort\fP mode) is sufficient to describe its behavior across all eight variations. Note that some instructions always read values of a fixed size. For example the boolean condition read by \fBJCN\fP is always one byte, no matter what modes are used.
In \fIreturn\fP mode the stacks are reversed. Effects on \fBwst\fP will instead affect \fBrst\fP, and effects on \fBrst\fP will instead affect \fBwst\fP. For example, \fBSTH\fP reads a byte from \fBwst\fP and writes it to \fBrst\fP, but \fBSTHr\fP reads a byte from \fBrst\fP and writes it to \fBwst\fP.
In \fIkeep\fP mode all the values on the left-hand side of the stack effect will also appear on the right-hand side before the outputs. For example, \fBSWP\fP is \fB(x y -- y x)\fP but \fBSWPk\fP is \fB(x y -- x y y x)\fP.
.SS INC
( x -- x+1 )
@ -72,6 +76,8 @@ Thus for regular instructions writing a "generic" effect (leaving sigils off val
.SS POP
( x -- )
\fBPOPk\fP is guaranteed to have no effect (it will not change the stack).
.SS NIP
( x y -- y )