cosmopolitan/libc/str/tpenc.S
Justine Tunney 9e3e985ae5 Make terminal ui binaries work well everywhere
Here's some screenshots of an emulator tui program that was compiled on
Linux, then scp'd it to Windows, Mac, and FreeBSD.

https://justine.storage.googleapis.com/blinkenlights-cmdexe.png
https://justine.storage.googleapis.com/blinkenlights-imac.png
https://justine.storage.googleapis.com/blinkenlights-freebsd.png
https://justine.storage.googleapis.com/blinkenlights-lisp.png

How is this even possible that we have a nontrivial ui binary that just
works on Mac, Windows, Linux, and BSD? Surely a first ever achievement.

Fixed many bugs. Bootstrapped John McCarthy's metacircular evaluator on
bare metal in half the size of Altair BASIC (about 2.5kb) and ran it in
emulator for fun and profit.
2020-10-19 06:38:31 -07:00

67 lines
2.8 KiB
ArmAsm

/*-*- mode:unix-assembly; indent-tabs-mode:t; tab-width:8; coding:utf-8 -*-│
vi: set et ft=asm ts=8 tw=8 fenc=utf-8 :vi
Copyright 2020 Justine Alexandra Roberts Tunney
This program is free software; you can redistribute it and/or modify │
it under the terms of the GNU General Public License as published by
the Free Software Foundation; version 2 of the License. │
This program is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of │
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software │
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
02110-1301 USA
*/
#include "libc/macros.h"
.source __FILE__
/ Encodes Thompson-Pike varint.
/
/ @param edi is int to encode
/ @return rax is word-encoded byte buffer
/ @note invented on a napkin in a new jersey diner
tpenc: .leafprologue
.profilable
mov %edi,%edi
xor %eax,%eax
cmp $127,%edi
jbe 3f
bsr %edi,%ecx
mov kTpenc-7*(1+1)(,%rcx,2),%ecx
1: mov %edi,%edx
shr $6,%edi
and $0b00111111,%dl
or $0b10000000,%al
or %dl,%al
shl $8,%rax
dec %cl
jnz 1b
2: or %ch,%al
3: or %rdi,%rax
.leafepilogue
.endfn tpenc,globl
.rodata
.align 4
kTpenc: .rept 4 # MSB10 (0x7FF)
.byte 1,0b11000000 # len,mark
.endr
.rept 5 # MSB15 (0xFFFF)
.byte 2,0b11100000 # len,mark
.endr
.rept 5 # MSB20 (0x1FFFFF)
.byte 3,0b11110000 # len,mark
.endr
.rept 5 # MSB25 (0x3FFFFFF)
.byte 4,0b11111000 # len,mark
.endr
.rept 6 # MSB31 (0xffffffff)
.byte 5,0b11111100 # len,mark
.endr
.zero 2
.endobj kTpenc