work on interrupts

src/interrupts.s

@@ -65,16 +65,15 @@ cop_handler_native:
 	pla
 
 	; When we get here, the X register contains the function number.
-	; A and Y may or may not contain parameters. None of those are
-	; expected to be preserved. The job here is just to jump to the
-	; right handler for the particular function being called, without
-	; modifying anything but the X register.
-
-	; Note that if a COP function takes a single 8/16-bit argument, it will be
-	; in A; if it takes two 8/16-bit arguments, they will be in A and Y.
-	; If the function takes more arguments, then the arguments will be packed
-	; into a structure, with the bank of the structure in A, and the
-	; address in that bank of the structure in Y.
+	; A/C, Y, and _Dp[0..7] may or may not contain parameters. None of
+	; those are expected to be preserved. The job here is just to jump
+	; to the right handler for the particular function being called,
+	; without modifying anything but the X register.
+	;
+	; Note that, other than using the X register specifically for the
+	; function number, arguments are passed into COP functions following
+	; function-specific protocols. Each function's arguments and return
+	; values are listed near the function itself.
 
 	; Now, we do an indirect, indexed jump through the jump table.
 	jmp (.kbank(cop_jump_table),x)
@@ -87,13 +86,30 @@ cop_jump_table:
 
 	.extern __program_start
 
+; Exit the calling program, effectively soft-rebooting the system.
+;
+; Arguments: None
+; Return value: None
 cop_exit:
 	jmp long:__program_start
 
 ; -----------------------------------------------------------------------------
+; Function 0: Exit
+;
+; Return the version number for the running kernel.
+;
+; Arguments: None
+; Return value: Version number in C
+;
+; Note:
+;		The return value is divided into three fields.
+; 		The low-order byte is the "micro" or "patch"
+;		number, while the low-order nybble of the high
+;		byte is the "minor" number, and the high nybble
+;		is the major number. This allows versions to be
+;		compared using 16-bit math operations.
 
 	.extern version_number
-
 cop_get_version:
 	lda long:version_number
 	cop_rti