added an old version of mikmod for dos

[dosdemo] / libs / oldmik / src / mirq.c

diff --git a/libs/oldmik/src/mirq.c b/libs/oldmik/src/mirq.c
new file mode 100644 (file)
index 0000000..96cbcf7
--- /dev/null
+++ b/libs/oldmik/src/mirq.c
@@ -0,0 +1,99 @@
+/*\r
+\r
+Name:\r
+MDMA.C\r
+\r
+Description:\r
+Some general purpose IRQ routines\r
+\r
+Portability:\r
+\r
+MSDOS: BC(y)   Watcom(y)       DJGPP(y)\r
+Win95: n\r
+Os2:   n\r
+Linux: n\r
+\r
+(y) - yes\r
+(n) - no (not possible or not useful)\r
+(?) - may be possible, but not tested\r
+\r
+*/\r
+#include <dos.h>\r
+#include <conio.h>\r
+#include "mirq.h"\r
+\r
+#define OCR1   0x20                    /* 8259-1 Operation control register */\r
+#define IMR1   0x21                    /* 8259-1 Mask register */\r
+\r
+#define OCR2   0xA0                    /* 8259-2 Operation control register */\r
+#define IMR2   0xA1                    /* 8259-2 Mask register */\r
+\r
+\r
+BOOL MIrq_IsEnabled(UBYTE irqno)\r
+/*\r
+       Returns true if the specified hardware irq is enabled.\r
+*/\r
+{\r
+       UBYTE imr=(irqno>7) ? IMR2 : IMR1;              /* interrupt mask register */\r
+       UBYTE msk=1<<(irqno&7);                                 /* interrupt mask */\r
+       return((inportb(imr) & msk) == 0);\r
+}\r
+\r
+\r
+BOOL MIrq_OnOff(UBYTE irqno,UBYTE onoff)\r
+/*\r
+       Use to enable or disable the specified irq.\r
+*/\r
+{\r
+       UBYTE imr=(irqno>7) ? IMR2 : IMR1;              /* interrupt mask register */\r
+       UBYTE ocr=(irqno>7) ? OCR2 : OCR1;              /* ocr */\r
+       UBYTE msk=1<<(irqno&7);                                 /* interrupt mask */\r
+       UBYTE eoi=0x60|(irqno&7);                               /* specific end-of-interrupt */\r
+       BOOL oldstate;\r
+\r
+       /* save current setting of this irq */\r
+       oldstate=((inportb(imr) & msk) == 0);\r
+\r
+       if(onoff){\r
+               outportb(imr,inportb(imr) & ~msk);\r
+               outportb(ocr,eoi);\r
+               if(irqno>7) MIrq_OnOff(2,1);\r
+       }\r
+       else{\r
+               outportb(imr,inportb(imr) | msk);\r
+       }\r
+\r
+       return oldstate;\r
+}\r
+\r
+\r
+void MIrq_EOI(UBYTE irqno)\r
+/*\r
+       Clears the specified interrupt request at the interrupt controller.\r
+*/\r
+{\r
+        outportb(0x20,0x20);\r
+        if(irqno>7) outportb(0xa0,0x20);\r
+}\r
+\r
+\r
+PVI MIrq_SetHandler(UBYTE irqno,PVI handler)\r
+{\r
+#ifdef __DJGPP__\r
+       _go32_dpmi_seginfo seginfo;\r
+#endif\r
+       PVI oldvect;\r
+       int vecno=(irqno>7) ? irqno+0x68 : irqno+0x8;\r
+#ifdef __DJGPP__\r
+       _go32_dpmi_get_protected_mode_interrupt_vector(vecno, &seginfo);\r
+       oldvect = seginfo.pm_offset;\r
+       seginfo.pm_offset = handler;\r
+       seginfo.pm_selector = _go32_my_cs();\r
+       _go32_dpmi_allocate_iret_wrapper(&seginfo);\r
+       _go32_dpmi_set_protected_mode_interrupt_vector(vecno, &seginfo);\r
+#else\r
+       oldvect=_dos_getvect(vecno);\r
+       _dos_setvect(vecno,handler);\r
+#endif\r
+       return oldvect;\r
+}\r