From fa21a8439f23b608448f1ce5f1f01c51a63ed258 Mon Sep 17 00:00:00 2001 From: Joel Sherrill Date: Fri, 17 Jul 1998 15:17:29 +0000 Subject: New files from Ralf Corsepius . His comments: * c/src/exec/score/tools/sh - NEW DIRECTORY - contains shgen Most of it should be self-explanatory. I am a little bit concerned about host-dependent features (getopt, floating point libraries). This shouldn't disturb much now, as this tool should be compileable on all gnu-based hosts and is only applicable for the sh. But in case somebody complains, we may need to add autoconf checks or even restructurize parts of rtems (IMO, rtems needs to be restructurized - remember the "turning rtems upside down" issue). --- tools/cpu/sh/sci.c | 157 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 157 insertions(+) create mode 100644 tools/cpu/sh/sci.c (limited to 'tools/cpu/sh/sci.c') diff --git a/tools/cpu/sh/sci.c b/tools/cpu/sh/sci.c new file mode 100644 index 0000000000..58be0e68bf --- /dev/null +++ b/tools/cpu/sh/sci.c @@ -0,0 +1,157 @@ +/* + * Copyright (c) 1998 Ralf Corsepius (corsepiu@faw.uni-ulm.de) + * + * See the file COPYING for copyright notice. + */ + +#include +#include +#include + +#include "sci.h" + +/* + n .. baudrate generator source 0,1,2,3 + + N .. BRR setting (0..255) + + Phi .. processor baud rate + + B .. bitrate + */ + +typedef struct sci_tab { + unsigned int B ; + unsigned int n ; + int N ; + double err ; + } sci_tab_t ; + +static unsigned int bitrate [] = { + 50, + 75, + 110, + 134, + 150, + 200, + 300, + 600, + 1200, + 1800, + 2400, + 4800, + 9600, + 19200, + 38400, + 57600, + 115200, + 230400, + 460800 +}; + +static sci_tab_t test_array[4] ; + +static void Compute( + unsigned int n, + unsigned int B, + unsigned int Phi, + struct sci_tab *entry ) +{ + int a = ( 32 << ( 2 * n ) ) * B ; + + entry->n = n ; + entry->B = B ; + entry->N = rint( ( Phi / a ) - 1.0 ) ; + + if ( ( entry->N > 0 ) && ( entry->N < 256 ) ) + entry->err = + ( ( Phi / ( (entry->N + 1) * a ) - 1.0 ) * 100.0 ); + else + entry->err = 100.0 ; +} + +static sci_tab_t *SelectN( + unsigned int B, + double Phi ) +{ + unsigned int i ; + struct sci_tab* best = NULL ; + + for ( i = 0 ; i < 4 ; i++ ) + { + double err ; + + Compute( i, B, Phi, &test_array[i] ); + err = fabs( test_array[i].err ); + + if ( best ) + { + if ( err < fabs( best->err ) ) + best = &test_array[i] ; + } + else + best = &test_array[i] ; + } + + return best ; +} + +int shgen_gensci( + FILE *file, + double Phi ) /* Processor frequency [Hz] */ +{ + unsigned int i ; + + fprintf( file, + "/*\n * Bitrate table for the serial devices (sci) of the SH at %.3f MHz\n" + " */\n\n", Phi / 1000000.0 ); + fprintf( file, + "/*\n" + " * n .. SMR bits 0,1 : baud rate generator clock source\n" + " * N .. BRR bits 0..7: setting for baud rate generator\n" + " * error .. percentual error to nominal bitrate\n" + " * Hitachi's HW manual recommends bitrates with an error less than 1%%\n" + " * We experienced values less than 2%% to be stable\n" + " */\n\n" ); + fprintf( file, "#include \n\n" ); + fprintf( file, + "static struct sci_bitrate_t {\n" + " unsigned char n ;\n" + " unsigned char N ;\n" + "} _sci_bitrates[] = {\n" + "/* n N error */\n" ); + + for ( i = 0 ; i < sizeof(bitrate)/sizeof(int) ; i++ ) + { + struct sci_tab* best = SelectN( bitrate[i], Phi ); + + if ( i > 0 ) + fprintf( file, ",\n" ); + fprintf( file, " { %1d, %3d } /* %+7.2f%% ; B%d */", + best->n, + best->N, + best->err, + best->B ); + } + + fprintf( file, "\n};\n\n" ); + + fprintf( file, + "int _sci_get_brparms( \n" + " tcflag_t cflag,\n" + " unsigned char *smr,\n" + " unsigned char *brr )\n" + "{\n" + " unsigned int offset ;\n\n" + " offset = ( cflag & ( CBAUD & ~CBAUDEX ) )\n" + " + ( ( cflag & CBAUDEX ) ? B38400 : 0 );\n" + " if ( offset == 0 ) return -1 ;\n" + " offset-- ;\n\n" + " *smr &= ~0x03;\n" + " *smr |= _sci_bitrates[offset].n;\n" + " *brr = _sci_bitrates[offset].N;\n\n" + " return 0;\n" + "}\n" ); + + return 0 ; +} -- cgit v1.2.3