cosmopolitan/libc/nexgen32e/uart.h

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/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│vi: set net ft=c ts=8 sts=2 sw=2 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 │
╠──────────────────────────────────────────────────────────────────────────────╣
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╠──────────────────────────────────────────────────────▌▀▄─▐──▀▄─▐▄─▐▄▐▄─▐▄─▐▄─│
αcτµαlly pδrταblε εxεcµταblε § telecommunications │
╚─────────────────────────────────────────────────────────────────────────────*/
#ifndef COSMOPOLITAN_LIBC_NEXGEN32E_UART_H_
#define COSMOPOLITAN_LIBC_NEXGEN32E_UART_H_
/**
* @fileoverview PC Serial Line Helpers (8250 UART 16550+).
*
* <p>These functions provide the baseline of PC telecommunications
* support that doesn't require switching context or cpu mode.
*
* <p>Example use cases:
* <ul>
* <li>Qemu stdio
* <li>Bare metal stdio
* <li>FIPS-170-2 SSH alternative
* <li>NIC for key-signing servers
* </ul>
*
* @see www.lammertbies.nl/comm/info/serial-uart.html
*/
#define COM1 0x0 /* offset in pc bios data area with port number (0x400) */
#define COM2 0x2
#define COM3 0x4
#define COM4 0x6
#define IRQ3 0x0b /* com2 interrupt number (irq3) */
#define IRQ4 0x0c /* com1 interrupt number (irq4) */
#define UART_DLAB (1 << 7) /* serial line conf mode bit */
#define UART_DLL 0 /* divisor latch register */
#define UART_DLM 1 /* divisor latch register */
#define UART_IIR 2 /* interrupt identification register */
#define UART_LCR 3 /* line control register */
#define UART_LSR 5 /* line status register */
#define UART_TTYDA (1 << 0) /* data available (rx ready) */
#define UART_TTYOE (1 << 1) /* overrun error */
#define UART_TTYPE (1 << 2) /* parity error */
#define UART_TTYFE (1 << 3) /* framing error */
#define UART_TTYBSR (1 << 4) /* break signal received */
#define UART_TTYTXR (1 << 5) /* serial thr empty (tx ready) */
#define UART_TTYIDL (1 << 6) /* serial thr empty and line idle */
#define UART_TTYEDF (1 << 7) /* erroneous data in fifo */
#if !(__ASSEMBLER__ + __LINKER__ + 0)
COSMOPOLITAN_C_START_
void sinit(unsigned short *ports, unsigned count, const char *config);
void sputc(unsigned char ch, int port);
int sgetc(int port);
void sputs(const char *s, int port);
void sflush(unsigned short *ports, unsigned count);
unsigned char slsr(int port);
COSMOPOLITAN_C_END_
#endif /* !(__ASSEMBLER__ + __LINKER__ + 0) */
#endif /* COSMOPOLITAN_LIBC_NEXGEN32E_UART_H_ */