From 29cd51b76067e02683b9b95f4ce2582eac8669e4 Mon Sep 17 00:00:00 2001
From: Nguyễn Gia Phong <mcsinyx@disroot.org>
Date: Fri, 28 Feb 2020 22:09:59 +0700
Subject: [mips] Finish chapter 3

---
 mips/chapter-3/exercise-7.s | 47 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 47 insertions(+)
 create mode 100644 mips/chapter-3/exercise-7.s

(limited to 'mips/chapter-3/exercise-7.s')

diff --git a/mips/chapter-3/exercise-7.s b/mips/chapter-3/exercise-7.s
new file mode 100644
index 0000000..924765d
--- /dev/null
+++ b/mips/chapter-3/exercise-7.s
@@ -0,0 +1,47 @@
+# print(hex(0b11001))
+	.text
+main:
+	li	$t0,	25		# t0 = 0b11001
+	li	$t1,	0		# t1 = 0
+	li	$t9,	9		# t9 = 9
+
+reverse:
+	beqz	$t0,	done		# if (!t0) goto done
+	andi	$t2,	$t0,	0xf	# t2 = t0 & 0xf
+	sra	$t0,	$t0,	4	# t0 >>= 4
+	sll	$t1,	$t1,	4	# t1 <<= 4
+	add	$t1,	$t1,	$t2	# t1 += t2
+	j	reverse			# goto reverse
+done:
+
+	li	$v0,	11		# print character
+	li	$a0,	48		# 0
+	syscall
+	li	$v0,	11		# print character
+	li	$a0,	120		# x
+	syscall
+	bnez	$t1,	print		# if (!t1) goto print
+	li	$v0,	11		# print character
+	li	$a0,	48		# 0
+	syscall
+	j	end			# goto end
+
+print:
+	beqz	$t1,	end		# if (!t1) goto end
+	andi	$t2,	$t1,	0xf	# t2 = t1 & 0xf
+	sra	$t1,	$t1,	4	# t1 >>= 4
+	addi	$a0,	$t2,	48	# a0 = chr(t2), sort of
+	ble	$t2,	$t9,	put	# if (t2 <= 9) goto put
+	addi	$a0,	$a0,	7	# a0 += 7
+put:
+	li	$v0,	11		# print character at a0
+	syscall
+	j	print			# goto print
+end:
+
+	li	$v0,	11		# print character
+	li	$a0,	10		# newline
+	syscall
+
+	li	$v0,	10		# terminate
+	syscall
-- 
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