... for the nested call FN error in ZX ROM ... ,h
ld c,l ;DE=address of DEF FN ... stack, HL=address of DEF FN parms
ldir ;transfer ... parms from stack to DEF FN places

...

... for the nested call FN error in ZX ROM ... ,h
ld c,l ;DE=address of DEF FN ... stack, HL=address of DEF FN parms
ldir ;transfer ... parms from stack to DEF FN places

...

... for the nested call FN error in ZX ROM ... ,h
ld c,l ;DE=address of DEF FN ... stack, HL=address of DEF FN parms
ldir ;transfer ... parms from stack to DEF FN places

...

... b,h
ld c,l ;DE=address of DEF FN parms ... b,h
ld c,l ;DE=address of DEF FN parms ...

... data
2 DEF FN p(a)=PEEK a+256 ... br /> 9900 LET a=FN p(23427): LET e=(60416 ... br /> 9905 LET r=FN p(23730): IF r& ... /> LET f(n,d)=FN p(b)+VAL p$(PEEK ... locate header
LET h=INT f(n,1): POKE ... h+1 TO h+7 STEP 2:
LET f(n,d)=FN ...

... reading,
[*][b]GO SUB FN a( "s","DEMO",3,0 ... 128 ),
[*][b]GO SUB FN a( "R","=200",3,0 ... ,
[*][b]GO SUB FN a( "C","DEMO",3,0 ... e as for SET1346
H=REFHEAD b=file#, returns IX ... and h(8)
I=INITIALISE n ...

... referenced by the "GO SUB FN a(...)" calls. This shows "proof ... br /> LET bhi=FN i(base): LET blo=FN o(base): LET ... base>=k32k):
DEF FN i(v)=INT (v/kFG ... ): DEF FN o(v)=FN l(v,kFG)
FN i(pointer),FN o(pointer)): GO TO ...

... referenced by the "GO SUB FN a(...)" calls. This shows "proof ... br /> LET bhi=FN i(base): LET blo=FN o(base): LET ... base>=k32k):
DEF FN i(v)=INT (v/kFG ... ): DEF FN o(v)=FN l(v,kFG)
FN i(pointer),FN o(pointer)): GO TO ...

... updated values for the FN (a) parameters to ... h=kC-k3 TO kC: LET h(h)=VAL VAL$ (""""+CHR$ (h+57)+""""): NEXT h ... :
LET g$=f$
922 RESTORE FN ... h=kC-k3 TO kC: POKE FN p(23639)+55,h ... +57: LET b=h(h): NEXT h:

... do; eg.:
GO SUB FN s(s$,b,d) => ... ; GO SUB FN a(A$,F$,b,c ... ,e) => LET bc=FN u(A$,H$,b,d)
with ...

... TAP2DSK.BAS
6000 DEF FN s(s$,b,d)=6500 ... : DEF FN t(n,t)=t+k1 ... "
RESTORE 6413: LET pp=FN p(23639)+k6: LET c ... k0: LET il=k0: DEF FN i(v)=INT (v/kFG ... ): DEF FN o(v)=FN l(v,kFG)
FN c()+(d$>="@" AND d$

... axis
50 LET h2=h*h: GO SUB 100: LET t1 ... />
53 LET p=x-h: LET ip=y:
FOR ... i=x-h TO x+h:
LET ix=i ... />
55 LET x=x+h*3
60 GO SUB ... />
100 LET t=FN m(FN t(),FN t()): RETURN
[/code ...

... .125:
RESTORE 9000: DEF FN p(a)=PEEK a+256 ... /> 9001 FOR a=FN p(23639) TO FN p(23627)-1:
9004 PRINT '"h=";h'"i=";i'"j=";j''
9011 FOR a=FN p(23627) TO FN p(23641)-2:
NEXT a
9014 PRINT '"h=";h'"i=";i'"j=";j'':

I use the Dijkstra algorithm for calculating paths, as it's simple & quick, although it needs a lot of memory (in Spectrum terms). It's easy to write it in Spectrum BASIC in a couple of dozen lines, but impossible to run it as it needs several meg of ...

... FN b$(G)+FN b$(K)+FN b$(H)+FN b$(L)+
; FN b$(V)+FN ... b$(X)+FN ... b$(B)+FN ... ; 1220 GO SUB FN R("H")
call gsRR ...

... /> 3051 DEF FN d(h$)=16^(LEN h$-1)*(CODE h$-48-(7 AND ... CODE h$>64))
+VAL (("FN ... d(h$(2 TO))+" AND LEN h$>1)+"0 ...

... that the nested and recursive FN methods were both overly complicated ... /> exx
push hl ;save H'L'
ld bc,(FRAMES ... ,NoOverflow
exx
ld h,1 ;numerator segment is 9 ...

[code]; THE 'DEF FN' COMMAND ROUTINE
org 0x1f60< ...
ld a, tk_def_fn ; DEF FN?
jp pass_by ; immediate jump ... , l ; HL
ld b, h ; to BC
call stk_store ...

... bc
ld b,h
ld c,l ... USR ScrDol0
; ... FN s$(row,col) ...
ScrDol0 ... de,hl
inc h ;HL=character set address
ld a,h
cp $40 ; ...

... ", "CONTINUE",
"COPY", "DATA", "DEF FN", "DIM", "DRAW", "ERASE", "FLASH", "FORMAT ... ( *s != 0 )
{
h = pear_perm[(h + *s++)&63];
}
return (unsigned char )h;
}

/* The ...

... ",
"COPY", "DATA", "DEF FN", "DIM", "DRAW", "ERASE", "FLASH ... )
{
int h = salt;
unsigned char ... 0 )
{
h = pear_perm[(h + *s++)&63];
... }
return (unsigned char)h;
}

...

... in the "h = h & 63" statement the 'h' variable is ... k$()
4 DEF FN b(a,b,c,d ... SUB 400
80 IF h$(rsl+1)" " THEN
220 GO SUB FN b(zh,63,1, ... br /> 320 GO SUB FN b(zh,63,1, ... br /> 410 GO SUB FN b(0,k,-1, ... br /> 420 GO SUB FN b(37,k,-1, ...

... line 10. It's function FN e(), which is defined as ... :
[code]10 DEF FN e(a,b,c,d ... ,e,f,g,h,i,j,k)=USR 60000 ... mentioned pixel block)
g,h,i,j: define a rectangle ... top left corner at (g,h) and bottom right corner at ...

... /> [CODE]1 DEF FN a(x,y,h,v)=USR 63000
25 LET i=FN a(5,5,20,15 ... /> OR 64
LD H,A
LD A,E ... br /> POP BC
INC H
DJNZ 63061
POP ... 8
ADD A,H
LD H,A
63089 DJNZ ... to supply the x,y,h,v and attribute value to ...

... br /> LET i=FN a(x,y,h,v,a)
ld h,a
ld a,l ... ;%01000000
LD H,A ;H =hi-byte of display ...
ADD A,H
LD H,A
a63089: ... bc,(a63094);B,C = h,v
ld hl, ...

... x, y, x+w, y+h need to be verified. This ... CLEAR 62999: DEF FN b(x,y,w,h,a)=USR 63000 ... =";y,"Column=";x: INPUT "Height=";h,"Width=";w:
INPUT "Attribute ... : LET x=INT x: LET h=INT h: LET w=INT w ...

... TO 1:
FOR h=0 TO 1
30 ... GOTO 60
50 NEXT h:
NEXT g:
... TO INT (n/16): READ h$: NEXT i
40 ... $: NEXT i
50 PRINT h$;l$[/code]

... n$=FN b$()+FN b$()+FN b$()+FN b$()+FN b$()+FN b$()+FN b$()+FN b$()< ...