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[/] [wbuart32/] [trunk/] [bench/] [cpp/] [uartsim.cpp] - Blame information for rev 2

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////////////////////////////////////////////////////////////////////////////////
//
// Filename:    uartsim.cpp
//
// Project:     wbuart32, a full featured UART with simulator
//
// Purpose:     To forward a Verilator simulated UART link over a TCP/IP pipe.
//
// Creator:     Dan Gisselquist, Ph.D.
//              Gisselquist Technology, LLC
//
////////////////////////////////////////////////////////////////////////////////
//
// Copyright (C) 2015-2016, Gisselquist Technology, LLC
//
// This program is free software (firmware): you can redistribute it and/or
// modify it under the terms of  the GNU General Public License as published
// by the Free Software Foundation, either version 3 of the License, or (at
// your option) any later version.
//
// This program is distributed in the hope that it will be useful, but WITHOUT
// ANY WARRANTY; without even the implied warranty of MERCHANTIBILITY 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.  (It's in the $(ROOT)/doc directory, run make with no
// target there if the PDF file isn't present.)  If not, see
// <http://www.gnu.org/licenses/> for a copy.
//
// License:     GPL, v3, as defined and found on www.gnu.org,
//              http://www.gnu.org/licenses/gpl.html
//
//
////////////////////////////////////////////////////////////////////////////////
//
//
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <poll.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <signal.h>
#include <ctype.h>
 
#include "uartsim.h"
 
void    UARTSIM::setup_listener(const int port) {
        struct  sockaddr_in     my_addr;
 
        signal(SIGPIPE, SIG_IGN);
 
        printf("Listening on port %d\n", port);
 
        m_skt = socket(AF_INET, SOCK_STREAM, 0);
        if (m_skt < 0) {
                perror("Could not allocate socket: ");
                exit(-1);
        }
 
        // Set the reuse address option
        {
                int optv = 1, er;
                er = setsockopt(m_skt, SOL_SOCKET, SO_REUSEADDR, &optv, sizeof(optv));
                if (er != 0) {
                        perror("SockOpt Err:");
                        exit(-1);
                }
        }
 
        memset(&my_addr, 0, sizeof(struct sockaddr_in)); // clear structure
        my_addr.sin_family = AF_INET;
        // Use *all* internet ports to this computer, allowing connections from
        // any/every one of them.
        my_addr.sin_addr.s_addr = htonl(INADDR_ANY);
        my_addr.sin_port = htons(port);
 
        if (bind(m_skt, (struct sockaddr *)&my_addr, sizeof(my_addr))!=0) {
                perror("BIND FAILED:");
                exit(-1);
        }
 
        if (listen(m_skt, 1) != 0) {
                perror("Listen failed:");
                exit(-1);
        }
}
 
UARTSIM::UARTSIM(const int port) {
        m_conrd = m_conwr = m_skt = -1;
        if (port == 0) {
                m_conrd = STDIN_FILENO;
                m_conwr = STDOUT_FILENO;
        } else
                setup_listener(port);
        setup(25);      // Set us up for (default) 8N1 w/ a baud rate of CLK/25
        m_rx_baudcounter = 0;
        m_tx_baudcounter = 0;
        m_rx_state = RXIDLE;
        m_tx_state = TXIDLE;
}
 
void    UARTSIM::kill(void) {
        // Close any active connection
        if (m_conrd >= 0)                                close(m_conrd);
        if ((m_conwr >= 0)&&(m_conwr != m_conrd))        close(m_conwr);
        if (m_skt >= 0) close(m_skt);
 
        m_conrd = m_conwr = m_skt = -1;
}
 
void    UARTSIM::setup(unsigned isetup) {
        if (isetup != m_setup) {
                m_setup = isetup;
                m_baud_counts = (isetup & 0x0ffffff);
                m_nbits   = 8-((isetup >> 28)&0x03);
                m_nstop   =((isetup >> 27)&1)+1;
                m_nparity = (isetup >> 26)&1;
                m_fixdp   = (isetup >> 25)&1;
                m_evenp   = (isetup >> 24)&1;
        }
}
 
int     UARTSIM::nettick(int i_tx) {
        int     o_rx = 1;
 
        if ((m_conrd < 0)&&(m_conwr<0)&&(m_skt>=0)) {
                // Can we accept a connection?
                struct  pollfd  pb;
 
                pb.fd = m_skt;
                pb.events = POLLIN;
                poll(&pb, 1, 0);
 
                if (pb.revents & POLLIN) {
                        m_conrd = accept(m_skt, 0, 0);
                        m_conwr = m_conrd;
 
                        if (m_conrd < 0)
                                perror("Accept failed:");
                }
        }
 
        if ((!i_tx)&&(m_last_tx))
                m_rx_changectr = 0;
        else    m_rx_changectr++;
        m_last_tx = i_tx;
 
        if (m_rx_state == RXIDLE) {
                if (!i_tx) {
                        m_rx_state = RXDATA;
                        m_rx_baudcounter =m_baud_counts+m_baud_counts/2;
                        m_rx_baudcounter -= m_rx_changectr;
                        m_rx_busy    = 0;
                        m_rx_data    = 0;
                }
        } else if (m_rx_baudcounter <= 0) {
                if (m_rx_busy >= (1<<(m_nbits+m_nparity+m_nstop-1))) {
                        m_rx_state = RXIDLE;
                        if (m_conwr >= 0) {
                                char    buf[1];
                                buf[0] = (m_rx_data >> (32-m_nbits-m_nstop-m_nparity))&0x0ff;
                                if (1 != send(m_conwr, buf, 1, 0)) {
                                        close(m_conwr);
                                        m_conrd = m_conwr = -1;
                                }
                        }
                } else {
                        m_rx_busy = (m_rx_busy << 1)|1;
                        // Low order bit is transmitted first, in this
                        // order:
                        //      Start bit (1'b1)
                        //      bit 0
                        //      bit 1
                        //      bit 2
                        //      ...
                        //      bit N-1
                        //      (possible parity bit)
                        //      stop bit
                        //      (possible secondary stop bit)
                        m_rx_data = ((i_tx&1)<<31) | (m_rx_data>>1);
                } m_rx_baudcounter = m_baud_counts;
        } else
                m_rx_baudcounter--;
 
        if (m_tx_state == TXIDLE) {
                struct  pollfd  pb;
                pb.fd = m_conrd;
                pb.events = POLLIN;
                if (poll(&pb, 1, 0) < 0)
                        perror("Polling error:");
                if (pb.revents & POLLIN) {
                        char    buf[1];
                        if (1 == recv(m_conrd, buf, 1, MSG_DONTWAIT)) {
                                m_tx_data = (-1<<(m_nbits+m_nparity+1))
                                        // << nstart_bits
                                        |((buf[0]<<1)&0x01fe);
                                if (m_nparity) {
                                        int     p;
 
                                        // If m_nparity is set, we need to then
                                        // create the parity bit.
                                        if (m_fixdp)
                                                p = m_evenp;
                                        else {
                                                p = (m_tx_data >> 1)&0x0ff;
                                                p = p ^ (p>>4);
                                                p = p ^ (p>>2);
                                                p = p ^ (p>>1);
                                                p &= 1;
                                                p ^= m_evenp;
                                        }
                                        m_tx_data |= (p<<(m_nbits+m_nparity));
                                }
                                m_tx_busy = (1<<(m_nbits+m_nparity+m_nstop+1))-1;
                                m_tx_state = TXDATA;
                                o_rx = 0;
                                m_tx_baudcounter = m_baud_counts;
                        }
                }
        } else if (m_tx_baudcounter == 0) {
                m_tx_data >>= 1;
                m_tx_busy >>= 1;
                if (!m_tx_busy)
                        m_tx_state = TXIDLE;
                else
                        m_tx_baudcounter = m_baud_counts;
                o_rx = m_tx_data&1;
        } else {
                m_tx_baudcounter--;
                o_rx = m_tx_data&1;
        }
 
        return o_rx;
}
 
int     UARTSIM::fdtick(int i_tx) {
        int     o_rx = 1;
 
        if ((!i_tx)&&(m_last_tx))
                m_rx_changectr = 0;
        else    m_rx_changectr++;
        m_last_tx = i_tx;
 
        if (m_rx_state == RXIDLE) {
                if (!i_tx) {
                        m_rx_state = RXDATA;
                        m_rx_baudcounter =m_baud_counts+m_baud_counts/2;
                        m_rx_baudcounter -= m_rx_changectr;
                        m_rx_busy    = 0;
                        m_rx_data    = 0;
                }
        } else if (m_rx_baudcounter <= 0) {
                if (m_rx_busy >= (1<<(m_nbits+m_nparity+m_nstop-1))) {
                        m_rx_state = RXIDLE;
                        if (m_conwr >= 0) {
                                char    buf[1];
                                buf[0] = (m_rx_data >> (32-m_nbits-m_nstop-m_nparity))&0x0ff;
                                if (1 != write(m_conwr, buf, 1)) {
                                        fprintf(stderr, "ERR while attempting to write out--closing output port\n");
                                        perror("UARTSIM::write() ");
                                        m_conrd = m_conwr = -1;
                                }
                        }
                } else {
                        m_rx_busy = (m_rx_busy << 1)|1;
                        // Low order bit is transmitted first, in this
                        // order:
                        //      Start bit (1'b1)
                        //      bit 0
                        //      bit 1
                        //      bit 2
                        //      ...
                        //      bit N-1
                        //      (possible parity bit)
                        //      stop bit
                        //      (possible secondary stop bit)
                        m_rx_data = ((i_tx&1)<<31) | (m_rx_data>>1);
                } m_rx_baudcounter = m_baud_counts;
        } else
                m_rx_baudcounter--;
 
        if ((m_tx_state == TXIDLE)&&(m_conrd >= 0)) {
                struct  pollfd  pb;
                pb.fd = m_conrd;
                pb.events = POLLIN;
                if (poll(&pb, 1, 0) < 0)
                        perror("Polling error:");
                if (pb.revents & POLLIN) {
                        char    buf[1];
                        int     nr;
                        if (1==(nr = read(m_conrd, buf, 1))) {
                                m_tx_data = (-1<<(m_nbits+m_nparity+1))
                                        // << nstart_bits
                                        |((buf[0]<<1)&0x01fe);
                                if (m_nparity) {
                                        int     p;
 
                                        // If m_nparity is set, we need to then
                                        // create the parity bit.
                                        if (m_fixdp)
                                                p = m_evenp;
                                        else {
                                                p = (m_tx_data >> 1)&0x0ff;
                                                p = p ^ (p>>4);
                                                p = p ^ (p>>2);
                                                p = p ^ (p>>1);
                                                p &= 1;
                                                p ^= m_evenp;
                                        }
                                        m_tx_data |= (p<<(m_nbits+m_nparity));
                                }
                                m_tx_busy = (1<<(m_nbits+m_nparity+m_nstop+1))-1;
                                m_tx_state = TXDATA;
                                o_rx = 0;
                                m_tx_baudcounter = m_baud_counts;
                        } else if (nr < 0) {
                                fprintf(stderr, "ERR while attempting to read in--closing input port\n");
                                perror("UARTSIM::read() ");
                                m_conrd = -1;
                        } // and we really don't care if nr == 0 except that
                        // the poll above is supposed to keep it from happening
                }
        } else if (m_tx_baudcounter == 0) {
                m_tx_data >>= 1;
                m_tx_busy >>= 1;
                if (!m_tx_busy)
                        m_tx_state = TXIDLE;
                else
                        m_tx_baudcounter = m_baud_counts;
                o_rx = m_tx_data&1;
        } else {
                m_tx_baudcounter--;
                o_rx = m_tx_data&1;
        }
 
        return o_rx;
}
 

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[/] [wbuart32/] [trunk/] [bench/] [cpp/] [uartsim.cpp] - Blame information for rev 2

Line No.	Rev	Author	Line
1	2	dgisselq	`////////////////////////////////////////////////////////////////////////////////`
2			`//`
3			`// Filename: uartsim.cpp`
4			`//`
5			`// Project: wbuart32, a full featured UART with simulator`
6			`//`
7			`// Purpose: To forward a Verilator simulated UART link over a TCP/IP pipe.`
8			`//`
9			`// Creator: Dan Gisselquist, Ph.D.`
10			`// Gisselquist Technology, LLC`
11			`//`
12			`////////////////////////////////////////////////////////////////////////////////`
13			`//`
14			`// Copyright (C) 2015-2016, Gisselquist Technology, LLC`
15			`//`
16			`// This program is free software (firmware): you can redistribute it and/or`
17			`// modify it under the terms of the GNU General Public License as published`
18			`// by the Free Software Foundation, either version 3 of the License, or (at`
19			`// your option) any later version.`
20			`//`
21			`// This program is distributed in the hope that it will be useful, but WITHOUT`
22			`// ANY WARRANTY; without even the implied warranty of MERCHANTIBILITY or`
23			`// FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License`
24			`// for more details.`
25			`//`
26			`// You should have received a copy of the GNU General Public License along`
27			`// with this program. (It's in the $(ROOT)/doc directory, run make with no`
28			`// target there if the PDF file isn't present.) If not, see`
29			`// <http://www.gnu.org/licenses/> for a copy.`
30			`//`
31			`// License: GPL, v3, as defined and found on www.gnu.org,`
32			`// http://www.gnu.org/licenses/gpl.html`
33			`//`
34			`//`
35			`////////////////////////////////////////////////////////////////////////////////`
36			`//`
37			`//`
38			`#include <stdio.h>`
39			`#include <stdlib.h>`
40			`#include <string.h>`
41			`#include <sys/types.h>`
42			`#include <sys/socket.h>`
43			`#include <poll.h>`
44			`#include <unistd.h>`
45			`#include <arpa/inet.h>`
46			`#include <signal.h>`
47			`#include <ctype.h>`
48
49			`#include "uartsim.h"`
50
51			`void UARTSIM::setup_listener(const int port) {`
52			`struct sockaddr_in my_addr;`
53
54			`signal(SIGPIPE, SIG_IGN);`
55
56			`printf("Listening on port %d\n", port);`
57
58			`m_skt = socket(AF_INET, SOCK_STREAM, 0);`
59			`if (m_skt < 0) {`
60			`perror("Could not allocate socket: ");`
61			`exit(-1);`
62			`}`
63
64			`// Set the reuse address option`
65			`{`
66			`int optv = 1, er;`
67			`er = setsockopt(m_skt, SOL_SOCKET, SO_REUSEADDR, &optv, sizeof(optv));`
68			`if (er != 0) {`
69			`perror("SockOpt Err:");`
70			`exit(-1);`
71			`}`
72			`}`
73
74			`memset(&my_addr, 0, sizeof(struct sockaddr_in)); // clear structure`
75			`my_addr.sin_family = AF_INET;`
76			`// Use all internet ports to this computer, allowing connections from`
77			`// any/every one of them.`
78			`my_addr.sin_addr.s_addr = htonl(INADDR_ANY);`
79			`my_addr.sin_port = htons(port);`
80
81			`if (bind(m_skt, (struct sockaddr *)&my_addr, sizeof(my_addr))!=0) {`
82			`perror("BIND FAILED:");`
83			`exit(-1);`
84			`}`
85
86			`if (listen(m_skt, 1) != 0) {`
87			`perror("Listen failed:");`
88			`exit(-1);`
89			`}`
90			`}`
91
92			`UARTSIM::UARTSIM(const int port) {`
93			`m_conrd = m_conwr = m_skt = -1;`
94			`if (port == 0) {`
95			`m_conrd = STDIN_FILENO;`
96			`m_conwr = STDOUT_FILENO;`
97			`} else`
98			`setup_listener(port);`
99			`setup(25); // Set us up for (default) 8N1 w/ a baud rate of CLK/25`
100			`m_rx_baudcounter = 0;`
101			`m_tx_baudcounter = 0;`
102			`m_rx_state = RXIDLE;`
103			`m_tx_state = TXIDLE;`
104			`}`
105
106			`void UARTSIM::kill(void) {`
107			`// Close any active connection`
108			`if (m_conrd >= 0) close(m_conrd);`
109			`if ((m_conwr >= 0)&&(m_conwr != m_conrd)) close(m_conwr);`
110			`if (m_skt >= 0) close(m_skt);`
111
112			`m_conrd = m_conwr = m_skt = -1;`
113			`}`
114
115			`void UARTSIM::setup(unsigned isetup) {`
116			`if (isetup != m_setup) {`
117			`m_setup = isetup;`
118			`m_baud_counts = (isetup & 0x0ffffff);`
119			`m_nbits = 8-((isetup >> 28)&0x03);`
120			`m_nstop =((isetup >> 27)&1)+1;`
121			`m_nparity = (isetup >> 26)&1;`
122			`m_fixdp = (isetup >> 25)&1;`
123			`m_evenp = (isetup >> 24)&1;`
124			`}`
125			`}`
126
127			`int UARTSIM::nettick(int i_tx) {`
128			`int o_rx = 1;`
129
130			`if ((m_conrd < 0)&&(m_conwr<0)&&(m_skt>=0)) {`
131			`// Can we accept a connection?`
132			`struct pollfd pb;`
133
134			`pb.fd = m_skt;`
135			`pb.events = POLLIN;`
136			`poll(&pb, 1, 0);`
137
138			`if (pb.revents & POLLIN) {`
139			`m_conrd = accept(m_skt, 0, 0);`
140			`m_conwr = m_conrd;`
141
142			`if (m_conrd < 0)`
143			`perror("Accept failed:");`
144			`}`
145			`}`
146
147			`if ((!i_tx)&&(m_last_tx))`
148			`m_rx_changectr = 0;`
149			`else m_rx_changectr++;`
150			`m_last_tx = i_tx;`
151
152			`if (m_rx_state == RXIDLE) {`
153			`if (!i_tx) {`
154			`m_rx_state = RXDATA;`
155			`m_rx_baudcounter =m_baud_counts+m_baud_counts/2;`
156			`m_rx_baudcounter -= m_rx_changectr;`
157			`m_rx_busy = 0;`
158			`m_rx_data = 0;`
159			`}`
160			`} else if (m_rx_baudcounter <= 0) {`
161			`if (m_rx_busy >= (1<<(m_nbits+m_nparity+m_nstop-1))) {`
162			`m_rx_state = RXIDLE;`
163			`if (m_conwr >= 0) {`
164			`char buf[1];`
165			`buf[0] = (m_rx_data >> (32-m_nbits-m_nstop-m_nparity))&0x0ff;`
166			`if (1 != send(m_conwr, buf, 1, 0)) {`
167			`close(m_conwr);`
168			`m_conrd = m_conwr = -1;`
169			`}`
170			`}`
171			`} else {`
172			`m_rx_busy = (m_rx_busy << 1)\|1;`
173			`// Low order bit is transmitted first, in this`
174			`// order:`
175			`// Start bit (1'b1)`
176			`// bit 0`
177			`// bit 1`
178			`// bit 2`
179			`// ...`
180			`// bit N-1`
181			`// (possible parity bit)`
182			`// stop bit`
183			`// (possible secondary stop bit)`
184			`m_rx_data = ((i_tx&1)<<31) \| (m_rx_data>>1);`
185			`} m_rx_baudcounter = m_baud_counts;`
186			`} else`
187			`m_rx_baudcounter--;`
188
189			`if (m_tx_state == TXIDLE) {`
190			`struct pollfd pb;`
191			`pb.fd = m_conrd;`
192			`pb.events = POLLIN;`
193			`if (poll(&pb, 1, 0) < 0)`
194			`perror("Polling error:");`
195			`if (pb.revents & POLLIN) {`
196			`char buf[1];`
197			`if (1 == recv(m_conrd, buf, 1, MSG_DONTWAIT)) {`
198			`m_tx_data = (-1<<(m_nbits+m_nparity+1))`
199			`// << nstart_bits`
200			`\|((buf[0]<<1)&0x01fe);`
201			`if (m_nparity) {`
202			`int p;`
203
204			`// If m_nparity is set, we need to then`
205			`// create the parity bit.`
206			`if (m_fixdp)`
207			`p = m_evenp;`
208			`else {`
209			`p = (m_tx_data >> 1)&0x0ff;`
210			`p = p ^ (p>>4);`
211			`p = p ^ (p>>2);`
212			`p = p ^ (p>>1);`
213			`p &= 1;`
214			`p ^= m_evenp;`
215			`}`
216			`m_tx_data \|= (p<<(m_nbits+m_nparity));`
217			`}`
218			`m_tx_busy = (1<<(m_nbits+m_nparity+m_nstop+1))-1;`
219			`m_tx_state = TXDATA;`
220			`o_rx = 0;`
221			`m_tx_baudcounter = m_baud_counts;`
222			`}`
223			`}`
224			`} else if (m_tx_baudcounter == 0) {`
225			`m_tx_data >>= 1;`
226			`m_tx_busy >>= 1;`
227			`if (!m_tx_busy)`
228			`m_tx_state = TXIDLE;`
229			`else`
230			`m_tx_baudcounter = m_baud_counts;`
231			`o_rx = m_tx_data&1;`
232			`} else {`
233			`m_tx_baudcounter--;`
234			`o_rx = m_tx_data&1;`
235			`}`
236
237			`return o_rx;`
238			`}`
239
240			`int UARTSIM::fdtick(int i_tx) {`
241			`int o_rx = 1;`
242
243			`if ((!i_tx)&&(m_last_tx))`
244			`m_rx_changectr = 0;`
245			`else m_rx_changectr++;`
246			`m_last_tx = i_tx;`
247
248			`if (m_rx_state == RXIDLE) {`
249			`if (!i_tx) {`
250			`m_rx_state = RXDATA;`
251			`m_rx_baudcounter =m_baud_counts+m_baud_counts/2;`
252			`m_rx_baudcounter -= m_rx_changectr;`
253			`m_rx_busy = 0;`
254			`m_rx_data = 0;`
255			`}`
256			`} else if (m_rx_baudcounter <= 0) {`
257			`if (m_rx_busy >= (1<<(m_nbits+m_nparity+m_nstop-1))) {`
258			`m_rx_state = RXIDLE;`
259			`if (m_conwr >= 0) {`
260			`char buf[1];`
261			`buf[0] = (m_rx_data >> (32-m_nbits-m_nstop-m_nparity))&0x0ff;`
262			`if (1 != write(m_conwr, buf, 1)) {`
263			`fprintf(stderr, "ERR while attempting to write out--closing output port\n");`
264			`perror("UARTSIM::write() ");`
265			`m_conrd = m_conwr = -1;`
266			`}`
267			`}`
268			`} else {`
269			`m_rx_busy = (m_rx_busy << 1)\|1;`
270			`// Low order bit is transmitted first, in this`
271			`// order:`
272			`// Start bit (1'b1)`
273			`// bit 0`
274			`// bit 1`
275			`// bit 2`
276			`// ...`
277			`// bit N-1`
278			`// (possible parity bit)`
279			`// stop bit`
280			`// (possible secondary stop bit)`
281			`m_rx_data = ((i_tx&1)<<31) \| (m_rx_data>>1);`
282			`} m_rx_baudcounter = m_baud_counts;`
283			`} else`
284			`m_rx_baudcounter--;`
285
286			`if ((m_tx_state == TXIDLE)&&(m_conrd >= 0)) {`
287			`struct pollfd pb;`
288			`pb.fd = m_conrd;`
289			`pb.events = POLLIN;`
290			`if (poll(&pb, 1, 0) < 0)`
291			`perror("Polling error:");`
292			`if (pb.revents & POLLIN) {`
293			`char buf[1];`
294			`int nr;`
295			`if (1==(nr = read(m_conrd, buf, 1))) {`
296			`m_tx_data = (-1<<(m_nbits+m_nparity+1))`
297			`// << nstart_bits`
298			`\|((buf[0]<<1)&0x01fe);`
299			`if (m_nparity) {`
300			`int p;`
301
302			`// If m_nparity is set, we need to then`
303			`// create the parity bit.`
304			`if (m_fixdp)`
305			`p = m_evenp;`
306			`else {`
307			`p = (m_tx_data >> 1)&0x0ff;`
308			`p = p ^ (p>>4);`
309			`p = p ^ (p>>2);`
310			`p = p ^ (p>>1);`
311			`p &= 1;`
312			`p ^= m_evenp;`
313			`}`
314			`m_tx_data \|= (p<<(m_nbits+m_nparity));`
315			`}`
316			`m_tx_busy = (1<<(m_nbits+m_nparity+m_nstop+1))-1;`
317			`m_tx_state = TXDATA;`
318			`o_rx = 0;`
319			`m_tx_baudcounter = m_baud_counts;`
320			`} else if (nr < 0) {`
321			`fprintf(stderr, "ERR while attempting to read in--closing input port\n");`
322			`perror("UARTSIM::read() ");`
323			`m_conrd = -1;`
324			`} // and we really don't care if nr == 0 except that`
325			`// the poll above is supposed to keep it from happening`
326			`}`
327			`} else if (m_tx_baudcounter == 0) {`
328			`m_tx_data >>= 1;`
329			`m_tx_busy >>= 1;`
330			`if (!m_tx_busy)`
331			`m_tx_state = TXIDLE;`
332			`else`
333			`m_tx_baudcounter = m_baud_counts;`
334			`o_rx = m_tx_data&1;`
335			`} else {`
336			`m_tx_baudcounter--;`
337			`o_rx = m_tx_data&1;`
338			`}`
339
340			`return o_rx;`
341			`}`
342