Forth like interpreter
Greg Ewing
greg at cosc.canterbury.ac.nz
Mon Mar 13 20:33:02 EST 2000
"Samuel A. Falvo II" wrote:
>
> Almost unanimously, they are. Want to see a great Forth interpretter? Here
> it is, in x86 assembly:
>
> LODSD
> JMP EAX
Two instructions? Far too much overhead! On a PDP11
a Forth inner interpreter is just one instruction:
INNER: JMP (R5)+
Machine code words end with JMP INNER, and a
threaded word looks like:
myword: JSR R5,INNER
DW word1
DW word2
DW word3
DW SEMI
SEMI: MOV (SP)+,R5
JMP INNER
--
Greg Ewing, Computer Science Dept,
+--------------------------------------+
University of Canterbury, | A citizen of NewZealandCorp, a |
Christchurch, New Zealand | wholly-owned subsidiary of USA Inc. |
greg at cosc.canterbury.ac.nz +--------------------------------------+
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