- no full featured xcpt for bootloaders

- clear bss


git-svn-id: http://moon:8086/svn/mips@29 a8ebac50-d88d-4704-bea3-6648445a41b3

src/bootloader/Makefile

@@ -31,34 +31,34 @@ ROMGEN=$(MIPS_HOME)/tools/romgen
 
 all: bootloader_flash
 
-libsys: startup_boot.S kernel_boot.S libsys_boot.c ../libsys/xcpt.c
+libsys: startup_boot.S kernel_boot.S libsys_boot.c
 	$(CC) $(CFLAGS) -c startup_boot.S -o startup.o
 	$(CC) $(CFLAGS) -c kernel_boot.S -o kernel.o
 	$(CC) $(CFLAGS) -c libsys_boot.c -o libsys.o
-	$(CC) $(CFLAGS) -c ../libsys/xcpt.c -o xcpt.o
 
 bootloader: libsys bootloader.c
 	$(CC) $(CFLAGS) -g -c bootloader.c
-	$(LD) $(LFLAGS) $(LIB_DIRS) startup.o kernel.o xcpt.o libsys.o bootloader.o -o $@.elf $(LIBS) >$@.map
+	$(LD) $(LFLAGS) $(LIB_DIRS) startup.o kernel.o libsys.o bootloader.o -o $@.elf $(LIBS) >$@.map
 	$(OBJDUMP) -D $@.elf > $@.dis
-	$(OBJCOPY) $@.elf -O binary $@.ROM.bin
+	$(OBJCOPY) $@.elf -j ROM --output-target=binary $@.ROM.bin
 	$(OBJCOPY) -O srec $@.elf $@.srec
-	$(ROMGEN) $@.ROM.bin 10 $(ENDIAN_FLAGS)
+	$(ROMGEN) $@.ROM.bin 11 $(ENDIAN_FLAGS)
 
 bootloader_flash: libsys bootloader_with_flash.c
 	$(CC) $(CFLAGS) -g -c bootloader_with_flash.c
 	$(CC) $(CFLAGS) -g -c ../cfiflash.c
 	$(LD) $(LFLAGS) $(LIB_DIRS) startup.o kernel.o libsys.o cfiflash.o bootloader_with_flash.o -o $@.elf $(LIBS) >$@.map
 	$(OBJDUMP) -D $@.elf > $@.dis
-	$(OBJCOPY) $@.elf -O binary $@.ROM.bin
+	$(OBJCOPY) $@.elf -j ROM --output-target=binary $@.ROM.bin
 	$(OBJCOPY) -O srec $@.elf $@.srec
 	$(ROMGEN) $@.ROM.bin 11 $(ENDIAN_FLAGS)
 
-test: libsys test.c ../libsys/irq.c ../libsys/xcpt.c
+test: libsys test.c ../libsys/irq.c ../libsys/kernel.S ../libsys/xcpt.c
 	$(CC) $(CFLAGS) -g -c test.c
 	$(CC) $(CFLAGS) -g -c ../libsys/irq.c
-	$(CC) $(CFLAGS) -g -c ../libsys/xcpt.c
+	$(CC) $(CFLAGS) -g -c ../libsys/kernel.S
-	$(LD) $(LFLAGS) $(LIB_DIRS) startup.o kernel.o libsys.o irq.o xcpt.o test.o -o $@.elf $(LIBS) >$@.map
+	$(CC) $(CFLAGS) -c ../libsys/xcpt.c -o xcpt.o
+	$(LD) $(LFLAGS) $(LIB_DIRS) startup.o kernel.o irq.o xcpt.o libsys.o test.o -o $@.elf $(LIBS) >$@.map
 	$(OBJDUMP) -D $@.elf > $@.dis
 	$(OBJCOPY) $@.elf -j ROM --output-target=binary $@.ROM.bin
 	$(OBJCOPY) -O srec $@.elf $@.srec

src/bootloader/bootloader.ld

@@ -34,7 +34,9 @@ SECTIONS
    .data ORIGIN(ram) :
    {
       _ram_start = ALIGN(4);
-     *(.*data) *(.*bss) *(.*common)
+      __bss_start = ALIGN(4);
+     *(.*bss)
+      _end = ALIGN(4);
    }  > ram
 
    .flash ORIGIN(flash) :

src/bootloader/kernel_boot.S

@@ -1,6 +1,3 @@
-#include <regdef.h>
-#include <xcpt_asm.h>
-
 		.file	"kernel.S"
 
 		.section .ktext,"ax"
@@ -16,178 +13,34 @@
 		addiu	$sp, -4
 		.endm
 
-LEAF(_xcpt_handler)
+_exc_handler:
-		.set noreorder
-		.set noat
-		/* Note: exceptions do not save and restore registers k0 and k1.
-		* on entry, k1 = exception class.
-		*/
 
-		/* allocate exception stack frame (on 8-byte boundary) */
+		.set	noreorder
-		subu k1, sp, XCP_SIZE
-		srl k1, 3 	/* shift right/left -> alligned on boundary */
-		sll k1, 3
 		
-		/* save enough registers to get by */
+		# Set Error LED and ExcCode LEDs
-		sw AT, XCP_AT(k1)
+		# Get Cause
-		sw v0, XCP_V0(k1)
+		mfc0	$26, $13
-		sw v1, XCP_V1(k1)
+		li 		$27, 0xC0000000
-		sw a0, XCP_A0(k1)
+		srl		$26, 2
-		sw a1, XCP_A1(k1)
+		andi	$26, 0x000F
-		sw a2, XCP_A2(k1)
+		or 		$26, $27
-		sw a3, XCP_A3(k1)
+		la 		$27, sys_led_port
-		sw sp, XCP_SP(k1)
+		sw 		$26, 0($27)
-		sw ra, XCP_RA(k1)
 
-		/* get coprocessor 0 exception state */
+		# wait for all interrupts = 0
-		mfc0 a0, CP0_CR
+$w4x:	mfc0	$26, $13
-		mfc0 a1, CP0_SR
+		nop
-		mfc0 a2, CP0_BADDR
+		srl		$26, 8
-		mfc0 a3, CP0_EPC
+		andi	$26, 0xFF
-
+		bnez	$26, $w4x
-		/* we can safely use AT now */
-		.set at
-
-		/* switch to using sp to point at exception frame */
-		move sp, k1
-		
-		/* nothing sensible to store for k0/k1, store zero */
-		sw zero, XCP_K0(sp)
-		sw zero, XCP_K1(sp)		
-
-		/* we are now interruptible: dump all remaining state
-		* into the exception stack frame.
-		*/
-		/* coprocessor exception state */
-		sw a0, XCP_CR(sp)
-		sw a1, XCP_SR(sp)
-		sw a2, XCP_BADDR(sp)
-		sw a3, XCP_EPC(sp)
-
-		/* mdhi and mdlo */
-		mfhi v0
-		mflo v1
-		sw v0, XCP_MDHI(sp)
-		sw v1, XCP_MDLO(sp)
-
-		/* Save all the other general registers.
-		* We save zero, s0-s7 and s8 as well, as instruction emulators (e.g. FP
-		* operations) and debuggers rely on all registers stored together in
-		* well-defined structure.
-		*/
-		sw zero, XCP_ZERO(sp)
-		sw t0, XCP_T0(sp)
-		sw t1, XCP_T1(sp)
-		sw t2, XCP_T2(sp)
-		sw t3, XCP_T3(sp)
-		sw t4, XCP_T4(sp)
-		sw t5, XCP_T5(sp)
-		sw t6, XCP_T6(sp)
-		sw t7, XCP_T7(sp)
-		sw s0, XCP_S0(sp)
-		sw s1, XCP_S1(sp)
-		sw s2, XCP_S2(sp)
-		sw s3, XCP_S3(sp)
-		sw s4, XCP_S4(sp)
-		sw s5, XCP_S5(sp)
-		sw s6, XCP_S6(sp)
-		sw s7, XCP_S7(sp)
-		sw t8, XCP_T8(sp)
-		sw t9, XCP_T9(sp)
-		sw gp, XCP_GP(sp)
-		sw s8, XCP_S8(sp)
-
-		/* I don't know what the following does. [rb] */
-		/* load our _gp pointer */
-#		la gp, _gp
-
-		/* and call the C exception handler */
-		move a0, sp	# arg1 = &xcp
-		subu sp, 16	# (arg save area)
-		j _xcpt_call
-		move ra, zero	# fake return address
-		
-		/* This strange call to _xcpt_call with zero return address is to
-		* help exception-aware debuggers to trace back over the exception event.
-		* We are basically interposing a bogus stackframe (with a zero return
-		* address) between the C exception handler and the actual machine
-		* exception.
-		*/
-$xcptrest:
-		.set noat
-		add AT, sp, 16
-		
-		/* at points to exception frame */
-$xcptrestother:
-		/* restore all state */
-		/* restore most general registers */
-		lw t0, XCP_T0(AT)
-		lw t1, XCP_T1(AT)
-		lw t2, XCP_T2(AT)
-		lw t3, XCP_T3(AT)
-		lw t4, XCP_T4(AT)
-		lw t5, XCP_T5(AT)
-		lw t6, XCP_T6(AT)
-		lw t7, XCP_T7(AT)
-		lw s0, XCP_S0(AT)
-		lw s1, XCP_S1(AT)
-		lw s2, XCP_S2(AT)
-		lw s3, XCP_S3(AT)
-		lw s4, XCP_S4(AT)
-		lw s5, XCP_S5(AT)
-		lw s6, XCP_S6(AT)
-		lw s7, XCP_S7(AT)
-		lw t8, XCP_T8(AT)
-		lw t9, XCP_T9(AT)
-		lw gp, XCP_GP(AT)
-		lw s8, XCP_S8(AT)
-
-		/* mdhi and mdlo */
-		lw v0, XCP_MDHI(AT)
-		lw v1, XCP_MDLO(AT)
-		mthi v0
-		mtlo v1
-
-		/* remaining general registers */
-		lw a0, XCP_A0(AT)
-		lw a1, XCP_A1(AT)
-		lw a2, XCP_A2(AT)
-		lw a3, XCP_A3(AT)
-		lw ra, XCP_RA(AT)
-
-		/* restore the exception-time status register */
-		.set noreorder
-		lw v0, XCP_SR(AT)
 		nop
-		mtc0 v0, CP0_SR
-		lw v1, XCP_V1(AT)
-		lw v0, XCP_V0(AT)
-		lw sp, XCP_SP(AT)
 		
-		/* we are not uninterruptible and can use k1 safely */
+		# Get return address
-		lw k1, XCP_EPC(AT)
+		mfc0	$26, $14
-		lw AT, XCP_AT(AT)
+
-		mtc0 k1, CP0_EPC
+		# Return
-		j	k1
+		nop
+		jr	$26
 		rfe
+		.set	reorder
 	
-		.set reorder
-		.set at
-END(_xcpt_handler)
-		
-		
-LEAF(_xcpt_call)
-		/* on entry: a0 == &xcp */
-		subu sp, 24
-		sw ra, 16(sp)
-		
-		/* punt out to _xcpt_deliver */
-		jal _xcpt_deliver
-		nop
-		lw ra, 16(sp)
-		addu sp, 24
-		beqz ra, $xcptrest
-		nop
-		j ra
-		nop
-END(_xcpt_call)	

src/bootloader/libsys_boot.c

@@ -17,7 +17,7 @@ void _exit(int reason)
 void libsys_init()
 {
 	// Initialzie interrupt support
-	interrupt_init();
+//	interrupt_init();
 }
 
 // MIPS specific
@@ -110,10 +110,9 @@ void _putchar(char c)
 	writechar(c);
 }
 
-int sputs(char *pStr)
+int sputs(char const *pStr)
 {
-	char *start;
+	char const *start = pStr;
-	start = pStr;
 
 	while(*pStr)
 		_putchar(*(pStr++));

src/bootloader/libsys_boot.h

@@ -64,7 +64,7 @@ uint32_t CP0_PRID_read(void);
 char readchar(void);
 void writechar(char c);
 int write(int file, char *ptr, int len);
-int sputs(char *pStr);
+int sputs(char const *pStr);
 void print_byte(char byte);
 void print_word(int word);
 void PrintBuffer8(uint8_t *pBuf, int nbpr, int len);

src/bootloader/startup_boot.S

@@ -27,6 +27,14 @@ _start:
 		# Invalidate D-Cache
 		cop0	34
 
+		# zero bss
+		la $8, __bss_start
+		la $9, _end
+$zeroise:		
+		sw $0, 0($8)
+		bne $8, $9, $zeroise
+		addiu	$8, 4
+
 _init:
 		# Call libsys_init
 		la $k0, libsys_init

src/bootloader/test.c

@@ -13,6 +13,8 @@ void main()
 
 	// UART: enable RX interrupt
 	*pUART0_stat |= (1 << 6);
+
+	CP0_SR_write(0x0060000D);
 	interrupt_enable(3);
 
 	sputs("Hello, world!\n");