add new dfboot loader - a complete revison of romboot code.

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@7492 3c298f89-4303-0410-b956-a3cf2f4a3e73

1 files changed, 88 insertions, 0 deletions

diff --git a/target/linux/at91-2.6/image/dfboot/src/_umodsi3.S b/target/linux/at91-2.6/image/dfboot/src/_umodsi3.S
new file mode 100644
index 000000000..e4aebe84c
--- /dev/null
+++ b/target/linux/at91-2.6/image/dfboot/src/_umodsi3.S
@@ -0,0 +1,88 @@
+/* # 1 "libgcc1.S" */
+@ libgcc1 routines for ARM cpu.
+@ Division routines, written by Richard Earnshaw, (rearnsha@armltd.co.uk)
+/* # 145 "libgcc1.S" */
+dividend	.req	r0
+divisor		.req	r1
+overdone	.req	r2
+curbit		.req	r3
+/* ip		.req	r12	*/
+/* sp		.req	r13	*/
+/* lr		.req	r14	*/
+/* pc		.req	r15	*/
+	.text
+	.globl	 __umodsi3
+	.type  __umodsi3       ,function
+	.align 0
+ __umodsi3      :
+	cmp	divisor, #0
+	beq	Ldiv0
+	mov	curbit, #1
+	cmp	dividend, divisor
+	movcc  	pc, lr
+Loop1:
+	@ Unless the divisor is very big, shift it up in multiples of
+	@ four bits, since this is the amount of unwinding in the main
+	@ division loop.  Continue shifting until the divisor is
+	@ larger than the dividend.
+	cmp	divisor, #0x10000000
+	cmpcc	divisor, dividend
+	movcc	divisor, divisor, lsl #4
+	movcc	curbit, curbit, lsl #4
+	bcc	Loop1
+Lbignum:
+	@ For very big divisors, we must shift it a bit at a time, or
+	@ we will be in danger of overflowing.
+	cmp	divisor, #0x80000000
+	cmpcc	divisor, dividend
+	movcc	divisor, divisor, lsl #1
+	movcc	curbit, curbit, lsl #1
+	bcc	Lbignum
+Loop3:
+	@ Test for possible subtractions.  On the final pass, this may
+	@ subtract too much from the dividend, so keep track of which
+	@ subtractions are done, we can fix them up afterwards...
+	mov	overdone, #0
+	cmp	dividend, divisor
+	subcs	dividend, dividend, divisor
+	cmp	dividend, divisor, lsr #1
+	subcs	dividend, dividend, divisor, lsr #1
+	orrcs	overdone, overdone, curbit, ror #1
+	cmp	dividend, divisor, lsr #2
+	subcs	dividend, dividend, divisor, lsr #2
+	orrcs	overdone, overdone, curbit, ror #2
+	cmp	dividend, divisor, lsr #3
+	subcs	dividend, dividend, divisor, lsr #3
+	orrcs	overdone, overdone, curbit, ror #3
+	mov	ip, curbit
+	cmp	dividend, #0			@ Early termination?
+	movnes	curbit, curbit, lsr #4		@ No, any more bits to do?
+	movne	divisor, divisor, lsr #4
+	bne	Loop3
+	@ Any subtractions that we should not have done will be recorded in
+	@ the top three bits of "overdone".  Exactly which were not needed
+	@ are governed by the position of the bit, stored in ip.
+	@ If we terminated early, because dividend became zero,
+	@ then none of the below will match, since the bit in ip will not be
+	@ in the bottom nibble.
+	ands	overdone, overdone, #0xe0000000
+	moveq  	pc, lr				@ No fixups needed
+	tst	overdone, ip, ror #3
+	addne	dividend, dividend, divisor, lsr #3
+	tst	overdone, ip, ror #2
+	addne	dividend, dividend, divisor, lsr #2
+	tst	overdone, ip, ror #1
+	addne	dividend, dividend, divisor, lsr #1
+	mov 	pc, lr
+Ldiv0:
+	str	lr, [sp, #-4]!
+	bl	 __div0       (PLT)
+	mov	r0, #0			@ about as wrong as it could be
+	ldmia	sp!, {pc}
+	.size  __umodsi3       , . -  __umodsi3
+/* # 320 "libgcc1.S" */
+/* # 421 "libgcc1.S" */
+/* # 433 "libgcc1.S" */
+/* # 456 "libgcc1.S" */
+/* # 500 "libgcc1.S" */
+/* # 580 "libgcc1.S" */