Make it work with new gcc version; use linker script to force entry code in page 0.

mips/boot.S

@@ -55,7 +55,7 @@ start_hack_for_disassembler:
 	la $sp, kernel_stack + KERNEL_STACK_SIZE
 
 	// Clear .bss
-	la $a0, _edata
+	la $a0, _bss
 	la $a1, _end
 1:	sw $zero, 0($a0)
 	bne $a1, $a0, 1b

mips/entry.S

@@ -17,6 +17,7 @@
 
 #define KERNEL_STACK_SIZE 0x1000
 	// The kernel stack.
+	.bss
 	.lcomm kernel_stack, KERNEL_STACK_SIZE
 
 	.globl run_idle
@@ -24,24 +25,30 @@
 	.set noat
 	.set noreorder
 
+	.text
+
 #define ARCH
 #define ASM
 #define __KERNEL__
 #include "arch.hh"
 
+	.org 0x000
 addr_000:
 #if 1
 	// TLB refill
 	lui $k0, 0x8000
 	lw $k1, 0x174($k0)	// directory
 	mfc0 $k0, $CP0_ENTRY_HI
+	// Entry high is address: 12 bit offset in page; 1 bit even/odd; 9 bit which page pair; 10 bit which table.
 	srl $k0, $k0, 19
-	andi $k0, $k0, 0xffc
+	andi $k0, $k0, 0xffc	// Bits 30:21 remain: which page table to get from directory.
 	addu $k0, $k0, $k1
-	lw $k0, 0($k0)
+	lw $k0, 0($k0)		// k0 is the page table.
 	beq $zero, $k0, zero_refill
 	mfc0 $k1, $CP0_ENTRY_HI
 	srl $k1, $k1, 10
+	// Bits 20:13 remain: which page pair to get from page table.
+	// (Only the lower half is used for this; the upper half contains pointers to the kPages.)
 	andi $k1, $k1, 0x7f8
 	addu $k0, $k0, $k1
 	lw $k1, 0($k0)
@@ -66,7 +73,8 @@ zero_refill:
 	jr $t9
 	nop
 #endif
-	.fill 0x100 - (. - addr_000)
+
+	.org 0x100
 addr_100:
 	// Cache error
 	move $k1, $ra
@@ -75,8 +83,8 @@ addr_100:
 	la $t9, cache_error
 	jr $t9
 	nop
-	.fill 0x180 - (. - addr_000) - 3 * 4
 
+	.org 0x180 - 3 * 4
 directory:	// 0x174
 	.word 0
 current:	// 0x178
@@ -92,9 +100,8 @@ addr_180:
 	la $t9, exception
 	jr $t9
 	nop
-	// This is annoying; it must fill it up so addr_200 is right.  For some
-	// reason .fill 0x200 - (. - addr_000) - 2 * 4 doesn't work here.
-	.fill 0x60
+
+	.org 0x200 - 2 * 4
 	.word 0x00000012	// 1f8	EntryLo data for idle page.
 	.word 0x80000000	// 1fc  A pointer to the current page.
 addr_200:
@@ -105,8 +112,8 @@ addr_200:
 	la $t9, interrupt
 	jr $t9
 	nop
-	.fill 0x280 - (. - addr_000)
 
+	.org 0x280
 start_idle:			// 280
 	// Wait for the next interrupt, then the first thread will be scheduled.
 	// It is impractical to try to call schedule, because for that the
@@ -221,3 +228,6 @@ save_regs:
 	la $ra, kernel_exit
 	jr $t9
 	nop
+
+	.set at
+	.set reorder

mips/init.ccp

@@ -310,7 +310,16 @@ void init (unsigned mem):
 
 	// Say we're handling an exception.  Since we're going to enter the idle task, allow access to cp0.
 	// All interrupts enter the CPU through the interrupt controller at IP2, so enable that.
-	cp0_set (CP0_STATUS, 0x1000ff13)
+	cp0_set (CP0_STATUS, 0x10000413)
+
+	for int a = 0; a < 0x300; a += 0x80:
+		kdebug("addr ")
+		kdebug_num(a)
+		kdebug(":")
+		for int b = 0; b < 0x10; b += 4:
+			kdebug(" ")
+			kdebug_num(*(unsigned *)(0x80000000 | (a + b)))
+		kdebug('\n')
 
 	kdebug ("entering idle task\n")
 	// Done; return to user space (the idle task).

mips/interrupts.ccp

@@ -50,13 +50,13 @@ static kThread *handle_exit ():
 				current->address_space->arch.asid = asids[0]
 				asids[0] = asids[asids[0]]
 			else:
-				static unsigned random = 1
-				current->address_space->arch.asid = random
-				// Overwrite used asid, so flush those values from tlb.
-				flush_tlb (random)
+				static unsigned random
 				++random
 				if random >= 64:
 					random = 1
+				current->address_space->arch.asid = random
+				// Overwrite used asid, so flush those values from tlb.
+				flush_tlb (random)
 			asids[current->address_space->arch.asid] = (unsigned)current->address_space
 	cp0_set (CP0_ENTRY_HI, current->address_space->arch.asid)
 	directory = current->address_space->arch.directory

mips/nanonote/iris.ld

@@ -0,0 +1,23 @@
+OUTPUT_ARCH(mips)
+ENTRY(__start)
+MEMORY
+{
+	ram	: ORIGIN = 0x80000000 , LENGTH = 32M
+}
+
+SECTIONS
+{
+	.text : { "mips/iris_elf-entry.o" (.text*) } > ram
+	.text : { *(.text*) } > ram
+	.rodata : { *(.rodata*) *(.note*) } > ram
+	.sdata : { *(.sdata*) } > ram
+	.data : { *(.data*) *(.scommon*) *(.reginfo*) } > ram
+
+	_gp = ABSOLUTE(.);
+	.got : { *(.got*) } > ram
+
+	_bss = ABSOLUTE(.);
+	.sbss : { *(.sbss*) } > ram
+	.bss : { *(.bss*) } > ram
+	_end = ABSOLUTE(.);
+}

mips/start.S

@@ -49,7 +49,7 @@ base:
 	addiu   $v1, $v1, 32
 
 	// Set a1 to start address of image.
-	addiu $a1, $ra, image - base
+	addiu $a1, $ra, image - base + ADDR0 - 0x80000000
 
 	// Set a2 to end address of image.
 	lw $a2, 0($ra)