From: David Gow <david@ingeniumdigital.com>
Date: Sun, 6 Jul 2014 01:46:52 +0000 (+0800)
Subject: now with fewer midnight-isms
X-Git-Url: https://git.ucc.asn.au/?a=commitdiff_plain;h=f06cfbc2d5986de9f9489e5cd9424231f310d471;p=ipdf%2Fcode.git

now with fewer midnight-isms
---

diff --git a/src/div_digits_asm.s b/src/div_digits_asm.s
index b11dd92..1ebf86f 100644
--- a/src/div_digits_asm.s
+++ b/src/div_digits_asm.s
@@ -2,27 +2,25 @@
 .globl div_digits
 .type div_digits, @function
 
-# div_digits(digits, div, size, res, rem)
-# divides an arbint in digits by uint64 div into res with remainder rem
-# Either res or rem may alias digits
-# digits = rdi, div = rsx, size = rdx, res = rcx, rem = r8
+# div_digits(digits, div, size, res)
+# divides an arbint in digits by uint64 div into res, returns remainder
+# res may alias digits
+# digits = rdi, div = rsx, size = rdx, res = rcx,
 div_digits:
-	movq %rdx, %r9
-	leaq -8(%rdi,%r9,8), %rdi	# We want to point to the end of the buffer (LSB)
-	leaq -8(%rcx,%r9,8), %rcx	# We want to point to the end of the buffer (LSB)
-	leaq -8(%r8,%r9,8), %r8		# We want to point to the end of the buffer (LSB)
+	movq %rdx, %r8
+	leaq -8(%rdi,%r8,8), %rdi	# We want to point to the end of the buffer (LSB)
+	leaq -8(%rcx,%r8,8), %rcx	# We want to point to the end of the buffer (LSB)
 	movq $0, %rdx
 loop:
 	movq (%rdi), %rax
 	divq %rsi			# rdx:rax/rsi => rax, rdx:rax%rsi => rdx
 	movq %rax, (%rcx)
-	movq %rdx, (%r8)
-	dec %r9
+	dec %r8
 	leaq -8(%rdi), %rdi
 	leaq -8(%rcx), %rcx
-	leaq -8(%r8), %r8
 	jnz loop
 end:
+	movq %rdx, %rax			# return the remainder
 	ret