From 772e87739c848a10a014d3118ff14bd0ca48b2d0 Mon Sep 17 00:00:00 2001
From: Eugen Wissner <belka@caraus.de>
Date: Tue, 2 Oct 2018 08:55:29 +0200
Subject: Replace memory.op.cmp with optimized equal version

Deprecate cmp.
Fix #68.
---
 arch/x64/linux/memory/equal.S | 59 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 59 insertions(+)
 create mode 100644 arch/x64/linux/memory/equal.S

(limited to 'arch/x64/linux/memory/equal.S')

diff --git a/arch/x64/linux/memory/equal.S b/arch/x64/linux/memory/equal.S
new file mode 100644
index 0000000..37a906a
--- /dev/null
+++ b/arch/x64/linux/memory/equal.S
@@ -0,0 +1,59 @@
+	.text
+
+/*
+ * equalMemory.
+ *
+ * rdi - r1 length
+ * rsi - r1 data.
+ * rdx - r2 length.
+ * rcx - r2 data.
+ */
+	.globl _D5tanya6memory2op11equalMemoryFNaNbNixAvxQdZb
+	.type _D5tanya6memory2op11equalMemoryFNaNbNixAvxQdZb, @function
+_D5tanya6memory2op11equalMemoryFNaNbNixAvxQdZb:
+		// Compare the lengths
+		cmp %rdx, %rdi
+		jne not_equal
+
+		mov %rcx, %rdi
+
+		// Check if we're aligned
+		cmp $0x08, %rdx
+		jc aligned_1
+		test $0x07, %edi
+		jz aligned_8
+
+	naligned:
+		cmpsb
+		jne not_equal
+
+		dec %rdx
+		test $0x07, %edi
+		jnz naligned
+
+	aligned_8:
+		mov %rdx,  %rcx
+		shr $0x03, %rcx
+
+		repe cmpsq
+		jne not_equal
+
+		and $0x07, %edx
+		jz equal
+
+	aligned_1: // Compare the remaining bytes
+		mov %rdx, %rcx
+		cmp $0x0, %rcx
+
+		repe cmpsb
+		jne not_equal
+
+	equal:
+		mov $0x01, %rax // Return 1
+		jmp end
+
+	not_equal:
+		xor %rax, %rax // Return 0
+
+	end:
+		ret
-- 
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