forth: Implement "(parseh)"

This commit is contained in:
Virgil Dupras 2020-03-18 21:52:55 -04:00
parent d874f20278
commit 548facac0b
4 changed files with 50 additions and 5 deletions

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@ -141,6 +141,7 @@ NOT f -- f Push the logical opposite of f
*** Strings ***
LITS x -- a Read following LIT and push its addr to a
SCMP a1 a2 -- n Compare strings a1 and a2. See CMP
SLEN a -- n Push length of str at a.
*** I/O ***

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@ -1,15 +1,52 @@
( requires core )
( requires core, str )
( string being sent to parse routines are always null
terminated )
: (parsec) ( a -- n f )
( apostrophe is ASCII 39 )
DUP C@ 39 = NOT IF 0 EXIT THEN ( -- a 0 )
DUP 2 + C@ 39 = NOT IF 0 EXIT THEN ( -- a 0 )
DUP C@ 39 = NOT IF 0 EXIT THEN ( a 0 )
DUP 2 + C@ 39 = NOT IF 0 EXIT THEN ( a 0 )
( surrounded by apos, good, return )
1 + C@ 1 ( -- n 1 )
1 + C@ 1 ( n 1 )
;
( returns negative value on error )
: hexdig ( c -- n )
( '0' is ASCII 48 )
48 -
DUP 0 < IF EXIT THEN ( bad )
DUP 10 < IF EXIT THEN ( good )
( 'a' is ASCII 97. 59 = 97 - 48 )
49 -
DUP 0 < IF EXIT THEN ( bad )
DUP 6 < IF 10 + EXIT THEN ( good )
( bad )
255 -
;
: (parseh) ( a -- n f )
( '0': ASCII 0x30 'x': 0x78 0x7830: 30768 )
DUP @ 30768 = NOT IF 0 EXIT THEN ( a 0 )
( We have "0x" suffix )
2 +
( validate slen )
DUP SLEN ( a l )
DUP 0 = IF DROP 0 EXIT THEN ( a 0 )
4 > IF DROP 0 EXIT THEN ( a 0 )
0 ( a r )
BEGIN
OVER C@
DUP 0 = IF DROP SWAP DROP 1 EXIT THEN ( r, 1 )
hexdig ( a r n )
DUP 0 < IF DROP DROP 1 EXIT THEN ( a 0 )
SWAP 16 * + ( a r*16+n )
SWAP 1 + SWAP ( a+1 r )
AGAIN
;
: (parse) ( a -- n )
(parsec) NOT SKIP? EXIT
(parseh) NOT SKIP? EXIT
(parsed) NOT SKIP? EXIT
( nothing works )
ABORT" unknown word! "

7
apps/forth/str.fs Normal file
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@ -0,0 +1,7 @@
: SLEN ( a -- n )
DUP ( astart aend )
BEGIN
DUP C@ 0 = IF -^ EXIT THEN
1 +
AGAIN
;

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@ -7,7 +7,7 @@ AVRABIN = zasm/avra
SHELLAPPS = zasm ed
SHELLTGTS = ${SHELLAPPS:%=cfsin/%}
# Those Forth source files are in a particular order
FORTHSRCS = core.fs parse.fs fmt.fs
FORTHSRCS = core.fs str.fs parse.fs fmt.fs
FORTHSRC_PATHS = ${FORTHSRCS:%=$(APPS)/forth/%}
CFSIN_CONTENTS = $(SHELLTGTS) cfsin/user.h
OBJS = emul.o libz80/libz80.o