From: luser.droog@nospicedham.gmail.com
On Monday, May 14, 2018 at 10:27:59 PM UTC-5, Rod Pemberton wrote:
> On Fri, 11 May 2018 20:29:46 -0700 (PDT)
> luserdroog wrote:
>
> > I've settled on using si for now. bp seems tempting for this, but
> > you always have to have a displacement even if it's zero because
> > mod=0 r/m=6 does something else. So using si I have
> >
> > mov si, sp
> > mov ax, [si] ; smaller encoding
> >
> > and
> >
> > mov si, sp
> > mov ax, [si+2]
> >
> > For giggles, here's my draft so far. In a form which should
> > be convenient to plug into my emulator.
> >
>
> If you're loading SI, you can use LODSW. It will index SI for you.
> Use CLD or STD to set the direction, increment or decrement, for
> indexing.
>
> > $ cat forth.h
> > #define NEXT HEX3(ad,ff,e8)
> > #define CHAR(x) *#x
> > #define CHAR2(x,y) CHAR(x),CHAR(y)
> > #define CHAR3(x,y,z) CHAR2(x,y),CHAR(z)
> > #define CHAR4(w,x,y,z) CHAR2(w,x),CHAR2(y,z)
> > #define CHAR5(w,x,y,z,a) CHAR4(w,x,y,z),CHAR(a)
> > #define HEX(y) 0x##y
> > #define HEX2(x,y) HEX(x),HEX(y)
> > #define HEX3(x,y,z) HEX2(x,y),HEX(z)
> > #define HEX4(w,x,y,z) HEX2(w,x),HEX2(y,z)
> > #define HEX5(w,x,y,z,a) HEX4(w,x,y,z),HEX(a)
> >
> > static inline int
> > forth(char *mem){
> > char image[] = {
> > 0, 4, CHAR4(d,r,o,p), HEX(58), NEXT,
> > 0, 4, CHAR4(s,w,a,p), HEX4(58,5b,50,53), NEXT,
> > 0, 3, CHAR3(d,u,p),0, HEX5(8b,ec,8b,5,50), NEXT,
> > 0, 4. CHAR4(o,v,e,r), HEX6(8b,ec,8b,45,2,50), NEXT,
> > 0, 3, CHAR3(r,o,t),0, HEX6(58,5b,59,53,50,51), NEXT,
> > 0, 4, CHAR4(-,r,o,t), HEX6(58,5b,59,50,51,53), NEXT,
> > 0, 5, CHAR5(2,d,r,o,p),0, HEX2(58,59), NEXT,
> > 0, 4, CHAR4(2,d,u,p), HEX4(8b,ec,8b,5),HEX5(8b,5d,2,53,50), NEXT,
> > 0, 5, CHAR5(2,s,w,a,p),0, HEX4(58,5b,59,5a),HEX4(53,50,52,51),
> > NEXT, 0, 4, CHAR4(?,d,u,p),
> > HEX4(8b,ec,8b,5),HEX2(85,c0),HEX3(74,1,58), NEXT, 0, 2, CHAR2(1,+),
> > HEX4(8b,ec,ff,5), NEXT, 0, 2, CHAR2(1,-), HEX4(8b,ec,ff,d), NEXT,
> > 0, 1, CHAR(+),0, HEX5(58,8b,ec,1,5), NEXT,
> > 0, 1, CHAR(-),0, HEX5(58,8b,ec,29,5), NEXT,
> > 0, 1, CHAR(*),0, HEX5(58,5b,f7,eb,50), NEXT,
> > };
> > memcpy(mem, image, sizeof image);
> > }
> >
> >
>
> It works, but ouch.
Agreed. The file did not remain in that form for long.
I hope you'll also look at my later posts from May 12
which reads more nicely.
> Word alignment?
My plan was to ignore this at first. The target is my
own 8086 emulator which is missing roughly 1/3 of the
full instruction set.
> Is there some reason why putc() or putchar() i.e., send characters
> directly to an open tmpfile() file, wouldn't work in your macros?
>
No, I just hadn't consider that! That would simplify quite a bit
from the later versions.
> > Need to stitch up the link fields somehow.
>
> Of course, &image[XX], provides the address: image+XX. However, you
> only have a byte to encode a length to the next primitive. You could
> subtract two addresses. The problem is that any time you insert or
> delete bytes into any Forth word within image[], /all/ of the XX
> indexes from there onwards to the end of the dictionary, become
> incorrect and must be manually adjusted, since their values have been
> hard coded. BTDT.
>
> Now, if you called putc() or putchar() in your macros to write the
> bytes out to a file, then you could create a wrapper routine for putc()
> or putchar(), say i_putc(), which also increments a counter variable
> every time you output a character to a file. This variable would give
> you the current index position within image[]. Any time the char was
> '\0', you'd save the counter to subtract to later subtract from the
> current counter to obtain the LFA offset. Of course, that would mean
> that you'd need to use something other than '\0' for word padding the
> name field, e.g., perhaps a space.
>
Yes, that does seem like a good approach. I've gone in a different
direction with more complicated macros. But I am tempted to backtrack
and build the image with smaller functional pieces which are then
combined.
Still a work in progress, but here's the latest draft. It's now split
into several files.
$ for i in ppnarg.h asm8086.h applyx.h forth.h ; do echo ---- $i: ---- ; cat
$i ; done && echo -- && cpp -P forth.h
---- ppnarg.h: ----
/*
* The PP_NARG macro evaluates to the number of arguments that have been
* passed to it.
*
* Laurent Deniau, "__VA_NARG__," 17 January 2006, (29 November
2007).
*/
#define PP_NARG(...) PP_NARG_(__VA_ARGS__,PP_RSEQ_N())
#define PP_NARG_(...) PP_ARG_N(__VA_ARGS__)
#define PP_ARG_N( \
_1, _2, _3, _4, _5, _6, _7, _8, _9,_10, \
_11,_12,_13,_14,_15,_16,_17,_18,_19,_20, \
_21,_22,_23,_24,_25,_26,_27,_28,_29,_30, \
_31,_32,_33,_34,_35,_36,_37,_38,_39,_40, \
_41,_42,_43,_44,_45,_46,_47,_48,_49,_50, \
_51,_52,_53,_54,_55,_56,_57,_58,_59,_60, \
_61,_62,_63,N,...) N
#define PP_RSEQ_N() \
63,62,61,60, \
59,58,57,56,55,54,53,52,51,50, \
49,48,47,46,45,44,43,42,41,40, \
39,38,37,36,35,34,33,32,31,30, \
29,28,27,26,25,24,23,22,21,20, \
19,18,17,16,15,14,13,12,11,10, \
9,8,7,6,5,4,3,2,1,0
---- asm8086.h: ----
#define LEA(to,m,r,r_m) to+0x8d,MRM(m,r,r_m)
#define MOV(to,m,r,r_m) to+0x8b,MRM(m,r,r_m)
#define ADD(to,m,r,r_m) to+0x03,MRM(m,r,r_m)
#define SUB(to,m,r,r_m) to+0x2b,MRM(m,r,r_m)
#define F -2
#define MRM(m,r,r_m) 0##m##r##r_m
#define Z 0
#define B 1
#define W 2
#define R 3
#define AX 0
#define CX 1
#define DX 2
#define BX 3
#define SP 4
#define BP 5
#define SI 6
#define DI 7
#define BX_SI 0
#define BX_DI 1
#define BP_SI 2
#define BP_DI 3
#define SI_ 4
#define DI_ 5
#define BP_ 6
#define BX_ 7
#define TEST(m,r,r_m) 0x85,MRM(m,r,r_m)
#define IMUL(m, r_m) 0xf7,MRM(m,5,r_m)
#define INC_(m, r_m) 0xff,MRM(m,0,r_m)
#define DEC_(m, r_m) 0xff,MRM(m,1,r_m)
#define JMP_(m, r_m) 0xff,MRM(m,5,r_m)
#define POP(r) 0x58+r
#define PUSH(r) 0x50+r
#define ADDAX 0x05
#define LODS 0xAD
#define JZ 0x74
---- applyx.h: ----
#include "ppnarg.h"
/* need extra level to force extra eval */
#define Paste(a,b) a ## b
#define XPASTE(a,b) Paste(a,b)
/* APPLYXn variadic X-Macro by M Joshua Ryan */
/* Free for all uses. Don't be a jerk. */
/* I got bored after typing 15 of these. */
[continued in next message]
--- SoupGate-Win32 v1.05
* Origin: you cannot sedate... all the things you hate (1:229/2)
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