patch-2.1.4 linux/arch/alpha/lib/copy_user.S

• Lines: 119
• Date: Mon Oct 14 17:02:45 1996
• Orig file: v2.1.3/linux/arch/alpha/lib/copy_user.S
• Orig date: Thu Jan 1 02:00:00 1970

diff -u --recursive --new-file v2.1.3/linux/arch/alpha/lib/copy_user.S linux/arch/alpha/lib/copy_user.S
@@ -0,0 +1,118 @@
+/*
+ * arch/alpha/lib/copy_user.S
+ *
+ * Copy to/from user space, handling exceptions as we go..  This
+ * isn't exactly pretty.
+ *
+ * This is essentially the same as "memcpy()", but with a few twists.
+ * Notably, we have to make sure that $0 is always up-to-date and
+ * contains the right "bytes left to copy" value (and that it is updated
+ * only _after_ a successful copy). There is also some rather minor
+ * exception setup stuff..
+ *
+ * NOTE! This is not directly C-callable, because the calling semantics are
+ * different:
+ *
+ * Inputs:
+ *	length in $0
+ *	destination address in $6
+ *	source address in $7
+ *	exception pointer in $8
+ *	return address in $28 (exceptions expect it there)
+ *
+ * Outputs:
+ *	bytes left to copy in $0
+ *
+ * Clobbers:
+ *	$1,$2,$3,$4,$5,$6,$7
+ */
+
+	.set noat
+	.align 3
+	.globl __copy_user
+	.ent __copy_user
+__copy_user:
+	ldq $5,0($8)
+	beq $0,$35
+	and $6,7,$3
+	addq $5,1,$1
+	stq $1,0($8)
+	beq $3,$36
+	subq $3,8,$3
+	.align 5
+$37:
+	ldq_u $1,0($7)
+	ldq_u $2,0($6)
+	extbl $1,$7,$1
+	mskbl $2,$6,$2
+	insbl $1,$6,$1
+	addq $3,1,$3
+	bis $1,$2,$1
+	stq_u $1,0($6)
+	subq $0,1,$0
+	addq $6,1,$6
+	addq $7,1,$7
+	beq $0,$41
+	bne $3,$37
+$36:
+	and $7,7,$1
+	bic $0,7,$4
+	beq $1,$43
+	beq $4,$48
+	ldq_u $3,0($7)
+	.align 5
+$50:
+	ldq_u $2,8($7)
+	subq $4,8,$4
+	extql $3,$7,$3
+	extqh $2,$7,$1
+	bis $3,$1,$1
+	stq $1,0($6)
+	addq $7,8,$7
+	subq $0,8,$0
+	addq $6,8,$6
+	bis $2,$2,$3
+	bne $4,$50
+$48:
+	beq $0,$41
+	.align 5
+$57:
+	ldq_u $1,0($7)
+	ldq_u $2,0($6)
+	extbl $1,$7,$1
+	mskbl $2,$6,$2
+	insbl $1,$6,$1
+	bis $1,$2,$1
+	stq_u $1,0($6)
+	subq $0,1,$0
+	addq $6,1,$6
+	addq $7,1,$7
+	bne $0,$57
+	br $31,$41
+	.align 4
+$43:
+	beq $4,$65
+	.align 5
+	.align 5
+$66:
+	ldq $1,0($7)
+	subq $4,8,$4
+	stq $1,0($6)
+	addq $7,8,$7
+	subq $0,8,$0
+	addq $6,8,$6
+	bne $4,$66
+$65:
+	beq $0,$41
+	ldq $2,0($7)
+	ldq $1,0($6)
+	mskql $2,$0,$2
+	mskqh $1,$0,$1
+	bis $2,$1,$2
+	stq $2,0($6)
+	bis $31,$31,$0
+$41:
+	stq $5,0($8)
+$35:
+	ret $31,($28),1
+	.end __copy_user