From 8afbbdd383d70741498151ad1a27c93c8e875a90 Mon Sep 17 00:00:00 2001
From: Peter Ferrie <peter.ferrie@gmail.com>
Date: Mon, 8 Nov 2021 08:09:12 -0800
Subject: [PATCH] shave some bytes

---
 Makefile           |   2 +-
 bin/sectorlisp.bin | Bin 512 -> 4116 bytes
 lisp.c             |   2 +-
 sectorlisp.S       |  52 ++++++++++++++++++++++-----------------------
 4 files changed, 27 insertions(+), 29 deletions(-)

diff --git a/Makefile b/Makefile
index b1d618a..5625dbc 100644
--- a/Makefile
+++ b/Makefile
@@ -22,7 +22,7 @@ sectorlisp.o: sectorlisp.S
 	$(AS) -g -mtune=i386 -o $@ $<
 
 sectorlisp.bin.dbg: sectorlisp.o
-	$(LD) -oformat:binary -Ttext=0x7600 -o $@ $<
+	$(LD) -oformat:binary -Ttext=0x0000 -o $@ $<
 
 sectorlisp.bin: sectorlisp.bin.dbg
 	objcopy -S -O binary sectorlisp.bin.dbg sectorlisp.bin
diff --git a/bin/sectorlisp.bin b/bin/sectorlisp.bin
index cd664257a32b0f41ed4140a858990b36666995af..1440505c0b6804efa4915ef5d182e795f140d0c2 100755
GIT binary patch
literal 4116
zcmeH@&ubGw6vtl{Vj$YJcxVtyTTeEqXrPzX30RUKYE9CZn9xIVD2O)?ooP;DAr-nz
zC^U!cQ3R2aYFR`O55mG;ZM7FsJZJ^YGh2<VAgMnxP7wb9&(0TS-ebP+y?K0+=O(~u
z9S0`>S(wbFvI&T#l5rT%rY=HkJOi<~JgMX*NKC?Gm|NV8IOemTUmLov4+lc#(<eT7
z5X1w3SHNtc06YeEAI^jKvD!4d3(v{Otkzh<YfzKf7ZRTJ&wUS<n+wq;7mHvm`z)$&
zw9W3ld550I3Glwzqk?HXif=^0K)O#>*duhy-o<rchrOd@l+HxNNhg1o?Mbb&U9Z1b
z{jkb@o$|A-{2lr7qu_JSxDjV<AoBX5zSd9r*tQ+?c8oS1kdyC=F&?esVJMc;*b?=U
z7pl3^8|?k+&me&*X?&7~Rc)@+SLD6;)^hQLAYod@8zPN6!rSE6wLFjZ8urQtx#(xP
z@-!^_*j0=BE1g5KfaWWmBlKk&Z;5(AIz!f<E}RjylDEOB#>dD7Y8hQNWQW{JCs#hm
z2{}!NNo;>Sq0u0Tuva(R?4613<qX~yQ$_EQoWcDr&uT`?d_mvyK_kGn`B}|f|7YbI
kLJFk*#$K+Z2q*%IfFhs>C<2OrBA^H;0*Zhl@P82a4V%LYIsgCw

delta 434
zcmXAjK}b|l6o${e^peDxh`<b{8b$;s6cki2?%Np>hz?R}vzT!eh?|0YpAw0}3v#$2
z%oy*jY9%3~$s<}=3lrX=O+~XQS~bzalQ&5c>M1t2JG40*`2O!d=TUOugr(YsuMHI&
zQ}eqW&LqU+@k<R`)EVp6FWcbwVCCky!rM*gTdE$EpEu%Jz$th|04;)@5XA5SD0~gG
zh1%i=mUL*jh<Bi5wtbd%tc9cW%+8`+3~>_tRpRq_<!7O`et(+};V`J*LAw@I+W19J
zxKS73O(qj0xe5;Poet8fgSB&~TX$`bKNTlOHpHPiliPyX4e|GiB~<bKg?U#K-fT*q
z=^kl&n1WnBgWt86S1qNm4iohY)+pMLHROjO{==O$Z_Ui5svqKI&C>iX-qRWUrPWtC
zN5`dI7n+RVMuhK~|8Bu55!1f3+$d%eJnKg1`KJs%p3>fgK^Oi19^TfaysAh}We>Bt
z*IyIK;8f^FgEI-qSSL@h-qQnDDUY#M@%hgi0;0M}ARHUTCpw!`FHDWJLV2CKN2KtP
Uf0K#+2C**(X}DY=t@K9uABKd?`v3p{

diff --git a/lisp.c b/lisp.c
index 36d8ad7..99c1d33 100644
--- a/lisp.c
+++ b/lisp.c
@@ -137,7 +137,7 @@ void PrintChar(unsigned char b) {
   if (write(1, &b, 1) == -1) exit(1);
 }
 
-void PrintString(char *s) {
+void PrintString(const char *s) {
   char c;
   for (;;) {
     if (!(c = s[0])) break;
diff --git a/sectorlisp.S b/sectorlisp.S
index af5be88..abed8b2 100644
--- a/sectorlisp.S
+++ b/sectorlisp.S
@@ -3,6 +3,7 @@
 ╞══════════════════════════════════════════════════════════════════════════════╡
 │ Copyright 2020 Justine Alexandra Roberts Tunney                              │
 │ Copyright 2021 Alain Greppin                                                 │
+│ Some size optimisations by Peter Ferrie                                      │
 │                                                                              │
 │ Permission to use, copy, modify, and/or distribute this software for         │
 │ any purpose with or without fee is hereby granted, provided that the         │
@@ -22,18 +23,18 @@
 
 .set ONE,		%bp
 .set NIL,		1
-.set ATOM_T,		9
-.set ATOM_QUOTE,	13
-.set ATOM_COND,		25
-.set ATOM_ATOM,		35
-.set ATOM_CAR,		45
-.set ATOM_CDR,		53
-.set ATOM_CONS,		61
-.set ATOM_EQ,		71
+.set ATOM_T,		23
+.set ATOM_QUOTE,	27
+.set ATOM_COND,		39
+.set ATOM_ATOM,		49
+.set ATOM_CAR,		59
+.set ATOM_CDR,		67
+.set ATOM_CONS,		75
+.set ATOM_EQ,		85
 
 .set g_token,	0x7800
 .set g_str,	0x0
-.set g_mem,	0x3600
+.set g_mem,	0x8000
 .set boot,	0x7c00
 
 ////////////////////////////////////////////////////////////////////////////////
@@ -45,30 +46,27 @@
 .globl	_start
 .code16
 
-_start:	jmp	.init				# some bios scan for short jump
+_start:	
 .type kSymbols,@object;
 kSymbols:
-	.ascii "NIL\0T\0QUOTE\0COND\0ATOM\0CAR\0CDR\0CONS\0EQ"
-
+	.ascii "NIL\0\xC0"
 .type .init,@function
-.init:	ljmp	$0x600>>4,$_begin		# end of bios data roundup page
-_begin:	push	%cs				# memory model cs=ds=es = 0x600
+.init:	ljmp	$0x7c00>>4,$_begin
+	.ascii "\0T\0QUOTE\0COND\0ATOM\0CAR\0CDR\0CONS\0EQ\0"
+
+_begin:	mov	$g_mem,%cx
+	mov	%cx,%fs				# fs = &g_mem
+	xor	%ax,%ax
+	mov	%cx,%di
+	cld
+	rep stosb				# clears our bss memory
+	push	%cs				# memory model cs=ds=es = 0x7c0
 	push	%cs
 	push	%cs
 	pop	%ds
 	pop	%es
-	mov	$kSymbols,%si
-	push	%si
-	xor	%di,%di				# mov g_str, %di
-	mov	$37,%cx
-	cld
-	rep movsb
-	pop	%cx
 	pop	%ss
 	mov	%cx,%sp
-	mov	$g_mem,%ax
-	mov	%ax,%fs				# fs = &g_mem
-	rep stosb				# clears our bss memory
 	mov	$NIL,ONE
 main:	mov	$'\n',%dl
 	call	GetToken
@@ -81,7 +79,7 @@ main:	mov	$'\n',%dl
 	jmp	main
 
 GetToken:					# GetToken():al, dl is g_look
-	mov	$g_token,%di
+	mov	%fs,%di				# mov $g_token,%di
 	mov	%di,%si
 1:	mov	%dl,%al
 	cmp	$' ',%al
@@ -149,7 +147,7 @@ GetObject:					# called just after GetToken
 	jne	1b
 	jmp	5f
 2:	pop	%si				# drop 1
-	mov	$g_token,%si
+	mov	%fs,%si				# mov $g_token,%si
 3:	scasb
 	jne	3b
 	cmp	(%di),%al
@@ -181,7 +179,7 @@ PutChar:
 	cmp	$'\r',%al			# don't clobber stuff
 	jne	.ret
 	mov	$'\n',%al
-	jmp	PutChar				# bx volatile, bp never used
+	jmp	PutChar				# bx volatile
 
 ////////////////////////////////////////////////////////////////////////////////