X-Git-Url: http://gitweb.hachti.de/?a=blobdiff_plain;f=programs%2Flibtest%2Fsrc%2Ffaculty.asm;fp=programs%2Flibtest%2Fsrc%2Ffaculty.asm;h=e002ff4df8a2621ac701e088404c9285e7fb3c52;hb=8fac3a64e23edb8f2cd4cdc28631d603075de709;hp=0000000000000000000000000000000000000000;hpb=dece501660c059d108e0b4586de6806bfb5b8cf4;p=h316.git

diff --git a/programs/libtest/src/faculty.asm b/programs/libtest/src/faculty.asm
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+* RECURSIVE FACULTY CALCULATION - RECURSIVE STACK DEMO
+* 
+* 
+* AUTHOR:
+* 
+* PHILIPP HACHTMANN
+* 
+* 
+* VERSIONS:
+* 
+*               1.0 - INITIAL AND FINAL VERSION (22.12.2007)
+* 
+* 
+* PURPOSE:
+* 
+* TO DEMONSTRATE THE SOFTWARE STACK'S ABILITIES.
+* THE PROGRAM RECURSIVELY CALCULATES THE FACULTY OF A NUMBER SUPPLIED
+* BY THE USER. RETURN ADDRESSES AND LOCAL DATA OF THE RECURSIVE ROUTINE
+* ARE PUSHED TO AND POPPED FROM THE STACK.
+* 
+* 
+* USAGE:
+* 
+* JUST ASSEMBLE, LOAD AND EXECUTE.
+* 
+* THE FACULTY ROUTINE CAN ALSO BE ACCESSED BY OTHER PROGRAMS. IT CAN
+* BE CALLED WITH
+*               JST     FACLTY
+* AND THE ARGUMENT IN THE A-REGISTER. THE RESULT WILL BE IN THE A-REGISTER
+* AFTERWARDS.
+* 
+* 
+********************************************************************************
+* 
+* 
+**** GLOBAL SETTINGS
+* 
+	SUBR	FACLTY,FAK	EXPORT RECURSIVE ROUTINE
+	REL			RELOCATEABLE MODE
+	ORG	'0		COUNT FROM ZERO
+*
+* 
+********************************************************************************
+*
+* 
+**** MAIN ROUTINE
+* 
+MAIN	CALL	S$INIT	INITIALIZE STACK POINTER
+*
+	CALL	F$W1	WRITE TO ASR
+	DAC	BANR	POINTER TO BANNER FORMAT
+	CALL	F$CB
+* 
+AGIN	CALL	F$W1	WRITE TO ASR
+	DAC	FMT1	USING THIS FORMAT STRING
+	CALL	F$CB	CLOSE BUFFERS
+* 
+	CALL	F$R1	READ FROM ASR
+	DAC	FMT2	WITH THIS FORMAT
+	CALL	F$AR	ARGUMENT PROCESSING ROUTINE
+	DEC	1	NUMBER OF WORDS IN ARGUMENT
+	DAC	NUM	POINTER TO ARGUMENT
+	CALL	F$CB	CLOSE BUFFERS
+* 
+	LDA	NUM	LOAD DATA
+	JST	FAK2	RUN RECURSIVE FACULTY ROUTINE
+	STA	NUM	SAVE RESULT BACK TO DATA
+* 
+	CALL	F$W1	WRITE TO ASR
+	DAC	FMT3	USING THIS FORMAT STRING
+	CALL	F$AR	ARGUMENT PROCESSING ROUTINE
+	DEC	1	NUMBER OF WORDS IN ARGUMENT
+	DAC	NUM	POINTER TO ARGUMENT
+	CALL	F$CB	CLOSE BUFFERS
+* 
+	CALL	F$W1
+	DAC	FMT4	READY MESSAGE
+	CALL	F$CB
+* 
+	HLT		HALT SYSTEM
+	JMP	AGIN	DO IT AGAIN - AND AGAIN....
+* 
+* 
+********************************************************************************
+* 
+*  
+**** RECURSIVE FACULTY CALCULATION!
+* 
+*       CALL FAK
+* 
+FAK	DAC	**
+	STA	ARG1
+	LDA	FAK	RETURN ADDRESS!
+	STA	RET	SAVE :-)
+	CALL	S$PUSM
+	DAC	ARG1
+	DEC	2	2 WORDS TO SAVE
+* 
+	LDA	ARG1
+	SUB	=1	MINUS 1
+	SNZ
+	JMP	NDY	WE ARE AT LEVEL 1, SO RETURN 1
+	JST	FAK	CALL RECURSIVELY!!!
+	CALL	S$POPM	RESTORE MEMORY
+	DAC	ARG1
+	DEC	2
+	CALL	M$11	NORMAL MULTIPLY
+	DAC	ARG1
+REST	JMP*	RET	RETURN THROUGH ANOTHER DOOR
+* 
+NDY	CALL	S$POPM	RESTORE MEMORY
+	DAC	ARG1
+	DEC	2
+	LDA	ARG1	SHOULD BE 1
+	JMP*	RET
+* 
+* 
+********************************************************************************
+* 
+*  
+**** RECURSIVE FACULTY CALCULATION! - ALTERNATIVE IMPLEMENTATION
+* 
+*       CALL FAK
+* 
+FAK2	DAC	**
+	STA	ARG
+* 
+	LDA	ARG
+	CAS	=1	COMPARE
+	JMP	AGO	A > 1 : DO IT AGAIN!
+	NOP		A = 1 : RETURN WITH A=1
+	NOP		A < 1 : RETURN WITH A=0
+	JMP*	FAK2	RETURN.
+* 
+AGO	LDA	FAK2	LOAD RETURN ADDRESS
+	CALL	S$PUSH	PUSH IT TO THE STACK
+	LDA	ARG	LOAD ARGUMENT
+	CALL	S$PUSH	PUSH IT TO THE STACK
+* 
+	SUB	=1	SUBSTRACT ONE.
+	JST	FAK2	CALL RECURSIVELY!
+*
+	CALL	S$POPM	RESTORE MEMORY
+	DAC	RET	COMFORTABLE REVERSE ORDER
+	DEC	2	COPY TWO WORDS FROM STACK
+* 
+	CALL	M$11	CALL INTEGER MULTIPLICATION
+	DAC	ARG	THIS IS THE ORIGINAL ARG AGAIN.
+	JMP*	RET	RETURN THROUGH ANOTHER DOOR
+* 
+* 
+****************************************
+* 
+* 
+**** VARIABLES AND CONSTANTS
+* 
+ARG1	DEC	0
+RET	DEC	0	RETURN ADDRESS BUFFER USED BY FAK
+ARG	DEC	0	ARGUMENT BUFFER USED BY FAK
+*
+NUM	DEC	0	ARGUMENT BUFFER USED BY THE MAIN ROUTINE
+* 
+BANR	BCI	20,(34H0RECURSIVE FACULTY CALCULATION 1.0)
+FMT1	BCI	10,(7H INPUT:) PROMPT FORMAT
+FMT2	BCI	10,(I1)
+FMT3	BCI	10,(7HRESULT:,I7)	OUTPUT FORMAT
+FMT4	BCI	10,(7H0READY.)		END MESSAGE
+* 
+* 
+********************************************************************************
+* 
+* 
+**** END OF PROGRAM
+* 
+	END
+* 
+* 
+********************************************************************************
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