1 files changed, 87 insertions, 0 deletions
diff --git a/include/support.h b/include/support.h
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+/**
+** SCCS ID: @(#)support.h	2.3        1/22/25
+**
+** @file	support.h
+**
+** @author	K. Reek
+** @author	Warren R. Carithers
+**
+** Declarations for functions provided in support.c, and
+** some hardware characteristics needed in the initialization.
+**
+*/
+
+#ifndef SUPPORT_H
+#define SUPPORT_H
+
+/*
+** Delay values
+**
+** Notes:  The parameter to the delay() function is ambiguous; it
+** purports to indicate a delay length, but that isn't really tied
+** to any real-world time measurement.
+**
+** On the original systems we used (dual 500MHz Intel P3 CPUs), each
+** "unit" was approximately one tenth of a second, so delay(10) would
+** delay for about one second.
+**
+** On the current machines (Intel Core i5-7500), delay(100) is about
+** 2.5 seconds, so each "unit" is roughly 0.025 seconds.
+**
+** Ultimately, just remember that THESE VALUES ARE APPROXIMATE AT BEST.
+*/
+#define DELAY_1_SEC         40
+#define DELAY_1_25_SEC      50
+#define DELAY_2_SEC         80
+#define DELAY_2_5_SEC      100
+#define DELAY_3_SEC        120
+#define DELAY_5_SEC        200
+#define DELAY_7_SEC        280
+#define DELAY_10_SEC       400
+
+#ifndef ASM_SRC
+/**
+** panic
+**
+** Called when we find an unrecoverable error, this routine disables
+** interrupts, prints a description of the error and then goes into a
+** hard loop to prevent any further processing.
+**
+** @param reason  NUL-terminated message to be printed.
+*/
+void panic( char *reason );
+
+/**
+** init_interrupts
+**
+** (Re)initilizes the interrupt system. This includes initializing the
+** IDT and the PIC. It is up to the user to enable processor interrupts
+** when they're ready.
+*/
+void init_interrupts( void );
+
+/*
+** install_isr
+**
+** Installs a second-level handler for a specific interrupt. Returns the
+** previously-installed handler for reinstallation (if desired).
+**
+** @param vector    the interrupt vector number
+** @param handler	the second-stage ISR function to be called by the stub
+**
+** @return a pointer to the previously-registered ISR
+*/
+void (*install_isr( int vector,
+		void ( *handler )(int,int) ) )( int, int );
+
+/*
+** Name:    delay
+**
+** See the comment above about the relative accuracy of the 'length'
+** parameter.
+*/
+void delay( int length );
+
+#endif  /* !ASM_SRC */
+
+#endif