Subversion Repositories xulalx25soc

;///////////////////////////////////////////////////////////////////////////////
;/
;/ Filename:	memtest.S
;/
;/ Project:	XuLA2 board
;/
;/ Purpose:	To test whether or not we can interface with the SDRAM on the
;/		XuLA2 board.
;/
;/
;/ Creator:	Dan Gisselquist, Ph.D.
;/		Gisselquist Technology, LLC
;/
;///////////////////////////////////////////////////////////////////////////////
;/
;/ Copyright (C) 2015, Gisselquist Technology, LLC
;/
;/ This program is free software (firmware): you can redistribute it and/or
;/ modify it under the terms of  the GNU General Public License as published
;/ by the Free Software Foundation, either version 3 of the License, or (at
;/ your option) any later version.
;/
;/ This program is distributed in the hope that it will be useful, but WITHOUT
;/ ANY WARRANTY; without even the implied warranty of MERCHANTIBILITY or
;/ FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
;/ for more details.
;/
;/ License:	GPL, v3, as defined and found on www.gnu.org,
;/		http://www.gnu.org/licenses/gpl.html
;/
;/
;///////////////////////////////////////////////////////////////////////////////
;/
;/
#define	LFSRFILL	0x000001
;/ #define	LFSRTAPS	0x004597f
#define	LFSRTAPS	0x0408b85
#define	SDRAMBASE	0x0800000
;/ #define	SDRAMLEN	0x0800000
#define	SDRAMLEN	0x0800000
#define	RAMSCOPE	0x011c
#define	ZIPSCOPE	0x011e
	.section .start
	.global	_start
	.type	_start,@function
_start:
	LDI	user_entry,R0
	MOV	R0,uPC
	; LDI	RAMSCOPE,R8
	; LDI	0x04000000,R9
	; STO	R9,(R8)
	RTU
	; // Capture what just happened
	; LDI	0x8c000000,R9
	; STO	R9,(R8)
	; NOP
	; 
	HALT
	.section .text
user_entry:
;/ #define	CLEAR_MEMORY
#ifdef	CLEAR_MEMORY
clear_memory:
	LDI	SDRAMBASE,R0
	LDI	SDRAMLEN,R1
	ADD	R0,R1
	CLR	R2
clear_memory_loop:
	STO	R2,(R0)
	ADD	1,R0
	CMP	R0,R1
	BGT	clear_memory_loop
end_clear_memory:
#endif
 
	LDI	LFSRFILL,R2
	LDI	LFSRTAPS,R3
	CLR	R12
 
write_test:
	LDI	SDRAMBASE,R0
	LDI	SDRAMLEN,R1
	MOV	R2,R7		; Copy our initial fill
	CMP	0,R2
	HALT.Z
;/ #define	WAIT_FOR_WRITE_SCOPE
#ifdef	WAIT_FOR_WRITE_SCOPE
	LDI	RAMSCOPE,R8
	LDI	0x01ffc,R9
	STO	R9,(R8)			; Reset the SDRAM scope
	NOP				; Give it a chance to reset
	LDI	0x10000000,R10
scope_not_ready:
	NOP
	LOD	(R8),R9
	TST	R10,R9
	BZ	scope_not_ready
#endif
 
write_test_loop:
	LSR	1,R2
	XOR.C	R3,R2
	MOV	R2,R4
 
	LSR	1,R2
	XOR.C	R3,R2
	MOV	R2,R5
 
	LSR	1,R2
	XOR.C	R3,R2		; wr_reg_ce = R2
 
	STO	R4,(R0)		; op = R4
	STO	R5,1(R0)	; dcdA = R5
	STO	R2,2(R0)	; instruction - R2
	ADD	3,R0
	SUB	3,R1
	CMP	3,R1
	BGE	write_test_loop
 
read_test:
	LDI	SDRAMBASE,R0
	LDI	SDRAMLEN,R1
;/ #define	WAIT_FOR_READ_SCOPE
#ifdef	WAIT_FOR_READ_SCOPE
	LDI	RAMSCOPE,R8
	LDI	0x01ffc,R9
	STO	R9,(R8)			; Reset the SDRAM scope
	NOP				; Give it a chance to reset
	LDI	0x10000000,R10
not_ready:
	NOP
	LOD	(R8),R9
	TST	R10,R9
	BZ	not_ready
#endif
;/
;/	RAM[49072] = 0x02b39ba ... not RAM[0].  What's going on here?
;/	
read_test_loop:
	LOD	(R0),R4
	LOD	1(R0),R5
	LOD	2(R0),R6
 
	LSR	1,R7
	XOR.C	R3,R7
	CMP	R7,R4
	TRAP.NZ	0
 
	LSR	1,R7
	XOR.C	R3,R7
	CMP	R7,R5
	TRAP.NZ	0
 
	LSR	1,R7
	XOR.C	R3,R7
	CMP	R7,R6
	TRAP.NZ	0
 
	ADD	3,R0
	SUB	3,R1
	CMP	3,R1
 
	BGE	read_test_loop
 
	ADD	1,R12
	BRA	write_test
;
;
;
;	0x0408b85
;	0x060ce47
;	0x070eca6
;	0x0387653
;	0x05cb0ac
;	0x02e5856
;	0x0172c2b
;	0x04b1d90
;	0x0258ec8
;	0x012c764
;	0x00963b2
;	0x004b1d9
;	0x042d369
;	0x061e231
;	0x0707a9d
;	...
;
;