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-rw-r--r--libc/bios/rawio.c327
1 files changed, 327 insertions, 0 deletions
diff --git a/libc/bios/rawio.c b/libc/bios/rawio.c
new file mode 100644
index 0000000..1bb0e4d
--- /dev/null
+++ b/libc/bios/rawio.c
@@ -0,0 +1,327 @@
+/*
+ * rawio.c - plagiarised from ../../bootblocks/trk_buf.c
+ */
+
+#include <stdio.h>
+#include <bios.h>
+#include <ctype.h>
+#include <malloc.h>
+#include "rawio.h"
+
+int rawio_disk_drive = 0;
+int rawio_disk_spt = 7;
+int rawio_disk_heads = 2;
+int rawio_disk_cyls = 0;
+
+static int last_drive = 0;
+static int data_len = 0;
+static long data_trk1 = 0;
+static char * data_buf1 = 0;
+static long data_trk2 = 0;
+static char * data_buf2 = 0;
+
+static long bad_track = -1; /* Track number of last unsuccesful read */
+
+static long rawio_get_dpt();
+
+void rawio_reset_disk()
+{
+ if( data_buf1 ) free(data_buf1);
+ if( data_buf2 ) free(data_buf2);
+ data_buf1 = data_buf2 = 0;
+ last_drive = rawio_disk_drive;
+
+ if( !(rawio_disk_drive & 0x80 ) )
+ {
+ rawio_disk_spt = 7; /* Defaults for reading Boot area. */
+ rawio_disk_heads = 2;
+ rawio_disk_cyls = 0;
+#ifdef DEBUG
+ fprintf(stderr, "reset_disk (hard): spt = %d, heads = %d, cyls = %d\n",
+ rawio_disk_spt,
+ rawio_disk_heads,
+ rawio_disk_cyls);
+#endif
+ }
+#if defined(__MSDOS__) || defined(__STANDALONE__)
+ else
+ {
+ /* Hard disk, get parameters from bios */
+ long dpt;
+ int v;
+
+ rawio_disk_spt = 17; /* Defaults for reading Boot area. */
+ rawio_disk_heads = 1;
+ rawio_disk_cyls = 0;
+
+ dpt = rawio_get_dpt(rawio_disk_drive);
+ v = ((dpt>>16) & 0xFF);
+ if( v == 0xFF || v <= (rawio_disk_drive&0x7F) ) return; /* Bad dpt */
+
+ rawio_disk_spt = (dpt & 0x3F); /* Max sector number 1-63 */
+ if( rawio_disk_spt == 0 ) rawio_disk_spt = 64; /* 1-64 ? */
+ rawio_disk_heads = ((dpt>>24) & 0xFF) + 1; /* Head count 1-256 */
+ rawio_disk_cyls = ((dpt>>8) & 0xFF) + ((dpt<<2) & 0x300) + 1;
+
+ /* Cyls count, unchecked, only needs != 0, if AMI 386 bios can be
+ * upto 4096 cylinder, otherwise BIOS limit is 1024 cyl.
+ */
+#ifdef DEBUG
+ fprintf(stderr, "reset_disk (soft): spt = %d, heads = %d, cyls = %d\n",
+ rawio_disk_spt,
+ rawio_disk_heads,
+ rawio_disk_cyls);
+#endif
+ }
+#endif
+}
+
+int rawio_read_lsector(sectno, buffer)
+long sectno;
+char* buffer;
+{
+ int tries = 6;
+ int rv;
+
+ int phy_s = 1;
+ int phy_h = 0;
+ int phy_c = 0;
+
+ if( rawio_disk_drive != last_drive ) rawio_reset_disk();
+
+ if( rawio_disk_spt < 0 || rawio_disk_spt > 63 || rawio_disk_heads < 1 )
+ {
+ phy_s = sectno;
+ rawio_reset_disk();
+
+#ifdef DEBUG
+ fprintf(stderr, "read_sector(%ld = %d,%d,%d)\n",
+ sectno, phy_c, phy_h, phy_s+1);
+#endif
+ }
+ else
+ {
+ phy_s = sectno%rawio_disk_spt;
+ phy_h = sectno/rawio_disk_spt%rawio_disk_heads;
+ phy_c = sectno/rawio_disk_spt/rawio_disk_heads;
+
+#ifdef DEBUG
+ fprintf(stderr, "read_sector(%ld = %d,%d,%d)\n",
+ sectno, phy_c, phy_h, phy_s+1);
+#endif
+ if( rawio_fetch_track_buf(phy_c, phy_h, phy_s) >= 0 )
+ {
+#ifdef DEBUG
+ fprintf(stderr, "read_sector: ftb worked\n");
+#endif
+ memcpy(buffer, data_buf1 + (phy_s % data_len) * 512, 512);
+ return 512;
+ }
+ }
+
+ data_len = -1; /* Zap the cache */
+ if( data_buf1 == 0 )
+ data_buf1 = malloc(512);
+ if( data_buf1 == 0 )
+ {
+ fprintf(stderr, "Cannot allocate memory for disk read!!!\n");
+ return 0;
+ }
+
+ fprintf(stderr, "WARNING: Single sector read\n");
+
+ do
+ {
+ rv = rawio_phy_read(rawio_disk_drive, phy_c, phy_h, phy_s+1, 1, data_buf1);
+ tries--;
+ if( rv ) fprintf(stderr, "Error in phy_read(%d,%d,%d,%d,%d,%d);\n",
+ rawio_disk_drive, phy_c, phy_h, phy_s+1, 1, data_buf1);
+ }
+ while(rv && tries > 0);
+
+ if(rv)
+ {
+#ifdef DEBUG
+ fprintf(stderr, "rawio failed\n");
+#endif
+ return 0;
+ }
+ else
+ {
+#ifdef DEBUG
+ fprintf(stderr, "rawio worked\n");
+#endif
+ memcpy(buffer, data_buf1, 512);
+ return 512;
+ }
+}
+
+rawio_fetch_track_buf(phy_c, phy_h, phy_s)
+int phy_c, phy_h, phy_s;
+{
+ long trk_no, t;
+ char * p;
+ int tries = 3;
+ int rv, nlen;
+
+ /* Big tracks get us short of memory so limit it. */
+ nlen = (rawio_disk_spt-1)/22;
+ nlen = (rawio_disk_spt+nlen)/(nlen+1);
+ trk_no = (long)phy_c*rawio_disk_heads*4+phy_h*4+phy_s/nlen+1;
+
+ if( data_len != nlen )
+ {
+ if( data_buf1 ) free(data_buf1);
+ if( data_buf2 ) free(data_buf2);
+ data_buf1 = data_buf2 = 0;
+ data_len = rawio_disk_spt;
+ }
+#ifdef DEBUG
+ fprintf(stderr,
+ "ftb: trk_no=%ld, data_trk1=%ld, data_buf1=%x\n",
+ trk_no,
+ data_trk1,
+ data_buf1);
+#endif
+ if( trk_no == bad_track ) return -1;
+
+ if( data_buf1 && trk_no == data_trk1 ) return 0;
+
+ /* Two cases:
+ * 1) buffer2 has the one we want, need to swap to make it most recent
+ * 2) Neither has it, need to swap to overwrite least recent.
+ */
+
+ /* So we always swap */
+ p = data_buf1; data_buf1 = data_buf2; data_buf2 = p;
+ t = data_trk1; data_trk1 = data_trk2; data_trk2 = t;
+
+#ifdef DEBUG
+ fprintf(stderr, "ftb swap: trk_no=%ld, data_trk1=%ld, data_buf1=%x\n",
+ trk_no,
+ data_trk1,
+ data_buf1);
+#endif
+ /* The other one right ? */
+ if( data_buf1 && trk_no == data_trk1 ) return 0;
+
+ /* If we get here we have to do a physical read ... */
+ /* into data_buf1. */
+
+ if( data_buf1 == 0 )
+ {
+ data_buf1 = malloc(rawio_disk_spt*512);
+
+#ifdef __ELKS__
+ fprintf(stderr, "Allocated buffer to %d\n", data_buf1);
+#endif
+ }
+ if( data_buf1 == 0 )
+ {
+ /* Is buf2 allocated ? Yes take it! */
+ data_buf1 = data_buf2; data_buf2 = 0; data_trk2 = -1;
+ }
+
+ bad_track = -1;
+ data_trk1 = -1;
+
+#ifdef DEBUG
+ fprintf(stderr, "ftb buf: trk_no=%ld, data_trk1=%ld, data_buf1=%x\n",
+ trk_no,
+ data_trk1,
+ data_buf1);
+#endif
+ /* Not enough memory for track read. */
+ if( data_buf1 == 0 ) return -1;
+
+ do /* the physical read */
+ {
+ rv = rawio_phy_read(rawio_disk_drive, phy_c, phy_h, phy_s/data_len+1, data_len,
+ data_buf1);
+ tries--;
+ if( rv ) fprintf(stderr, "Error in phy_read(%d,%d,%d,%d,%d,%d);\n",
+ rawio_disk_drive, phy_c, phy_h, phy_s/data_len+1, data_len, data_buf1);
+ }
+ while(rv && tries > 0);
+
+ /* Disk error, it'll try one at a time, _very_ slowly! */
+ if(rv)
+ {
+ bad_track = trk_no;
+ return -1;
+ }
+
+ /* Yes! */
+ data_trk1 = trk_no;
+ return 0;
+}
+
+#if defined(__MSDOS__) || defined(__STANDALONE__)
+rawio_phy_read(drive, cyl, head, sect, length, buffer)
+{
+#asm
+ push bp
+ mov bp,sp
+
+ push es
+ push ds
+ pop es
+
+ mov dl,[bp+2+_rawio_phy_read.drive]
+ mov ch,[bp+2+_rawio_phy_read.cyl]
+ mov dh,[bp+2+_rawio_phy_read.head]
+ mov bx,[bp+2+_rawio_phy_read.buffer]
+
+ mov ax,[bp+2+_rawio_phy_read.cyl] ! Bits 10-11 of cylinder, AMI BIOS.
+ mov cl,#4
+ sar ax,cl
+ and al,#$C0
+ xor dh,al
+
+ mov cl,[bp+2+_rawio_phy_read.sect]
+ and cl,#$3F
+ mov ax,[bp+2+_rawio_phy_read.cyl] ! Bits 8-9 of cylinder.
+ sar ax,#1
+ sar ax,#1
+ and al,#$C0
+ or cl,al
+
+ mov al,[bp+2+_rawio_phy_read.length]
+ mov ah,#$02
+ int $13
+ jc read_err
+ mov ax,#0
+read_err:
+
+ pop es
+ pop bp
+#endasm
+}
+
+long
+rawio_get_dpt(drive)
+{
+#asm
+ push bp
+ mov bp,sp
+
+ push di
+ push es
+
+ mov dl,[bp+2+_rawio_get_dpt.drive]
+
+ mov ah,#$08
+ int $13
+ jnc func_ok
+ mov cx,ax
+ mov dx,#-1
+func_ok:
+ mov ax,cx
+
+ pop es
+ pop di
+ pop bp
+#endasm
+}
+#endif
+
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