diff options
| author | Ben Burwell <ben@benburwell.com> | 2015-04-01 20:29:53 -0400 |
|---|---|---|
| committer | Ben Burwell <ben@benburwell.com> | 2015-04-01 20:29:53 -0400 |
| commit | 2b30f30a330ee9bc9feb9ec4e55c8b6f3e6eb8fe (patch) | |
| tree | 08d7be1d815e1ae676eab5c734438ba048b854d1 /printer.c | |
| parent | e282a861d5868868940b449681f2ee5da3e439e8 (diff) | |
as of 2013-11-182013-11-18
Diffstat (limited to 'printer.c')
| -rw-r--r-- | printer.c | 157 |
1 files changed, 157 insertions, 0 deletions
diff --git a/printer.c b/printer.c new file mode 100644 index 0000000..840d811 --- /dev/null +++ b/printer.c @@ -0,0 +1,157 @@ +/**
+ * Operating Systems
+ * Mod 6
+ * Averill and Ben
+ * Writing awesome printer stuff.
+ */
+
+#include <dos.h>
+#include <stdio.h>
+#include "mpx.h";
+
+void interrupt (*vect0f)();
+dcb prt;
+
+int prt_opened;
+
+int prt_open(int * prt_flag) {
+ unsigned char imr;
+ unsigned char pcr;
+
+ disable();
+
+ if (prt_opened == NULL || prt_opened == 0) {
+ prt_opened = 1;
+ } else {
+ return -2;
+ }
+
+ // set up vector interrupt
+ vect0f = getvect(0x0f);
+ setvect(0x0f, &prt_int);
+
+ // enable printer interrupts on 8259
+ imr = inportb(IMR);
+ imr = imr & 0x7f; //0111-1111
+ outportb(IMR, imr);
+
+ // clear init bit (b2), set select bit (b3)
+ // 0000 1010
+ outportb(PCR, 0x0a);
+
+ // initialize a printer control block
+ prt.current_op = NO_OP;
+ prt.event_flag = prt_flag;
+ prt.count = 0;
+
+ enable();
+ return 0;
+}
+
+int prt_write(char far *buffer, int *length) {
+ unsigned char pcr;
+
+ disable();
+ // check that prt isn't busy
+ if (prt.current_op != NO_OP) {
+ return -2;
+ }
+
+ // check that length is valid
+ if (*length < 1) {
+ return -3;
+ }
+
+ //save buffer and length in prt dcb
+ prt.buffer = buffer;
+ prt.length = length;
+ prt.current_op = WRITE_OP;
+ prt.count = 0;
+
+ // enable printer interrupts on PCR
+ // 0001 1010
+ outportb(PCR, 0x1a);
+
+ // strobe printer
+ // 0001 1011
+ outportb(PCR, 0x1d);
+
+ // print a null
+ // NOTE: something is not right here because when i print something
+ // other than a null it still doesn't print
+ outportb(PDR, 0x00);
+
+ // unstrobe printer
+ // 0001 1010
+ outportb(PCR, 0x1c);
+
+ enable();
+ return 0;
+}
+
+int prt_close() {
+ unsigned char pcr;
+ unsigned char imr;
+
+ disable();
+
+ // reset printer
+ // set init bit (b2) to 1 all else clear
+ // 0000 0100
+ outportb(PCR, 0x04);
+
+ //disable printer interrupts
+ imr = inportb(IMR);
+ imr = imr | 0x80;
+ outportb(IMR, imr);
+
+ // restore ms-dos's printer interrupt vector
+ setvect(0x0f, vect0f);
+
+ enable();
+ return 0;
+}
+
+void interrupt prt_int() {
+ unsigned char pcr;
+ int *lst_stk;
+ float temp;
+
+ lst_stk = _BP;
+
+ // if no more char to write
+ if (prt.count == *(prt.length)) {
+ // disable printer interrupts at PCR
+ // clear b4 on PCR
+ pcr = inportb(PCR);
+ pcr = pcr & 0xef; // 1110-1111
+ outportb(PCR, pcr);
+
+ // set event flag
+ prt.current_op = NO_OP;
+ *(prt.event_flag) = 1;
+
+ // call io-complete
+ // TODO: the book says (pg 86) that there should be stuff passed to io-complete
+ IO_complete(2, lst_stk);
+
+ // send end of interrupt signal
+ outportb(0x20, 0x20);
+ } else {
+
+ // strobe printer
+ // 0001 1101
+ outportb(PCR, 0x1d);
+
+ // write char to PDR
+ outportb(PDR, prt.buffer[prt.count]);
+ prt.count++;
+
+ // unstrobe printer
+ // 0001 1100
+ outportb(PCR, 0x1c);
+ }
+
+ // send EOI
+ outportb(0x20, 0x20);
+}
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