shave some bytes

This commit is contained in:
Peter Ferrie 2021-11-08 08:09:12 -08:00
parent 21383822a7
commit 8afbbdd383
4 changed files with 27 additions and 29 deletions

View file

@ -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

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2
lisp.c
View file

@ -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;

View file

@ -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
////////////////////////////////////////////////////////////////////////////////