Added lab7 option 2

lab7/riscv1.asm

@@ -0,0 +1,72 @@
+	.data
+a: .word 10, -20, 30, -40, 50
+b: .word 2, 4, -5, -8, 3
+c: .space 20
+
+	.text
+	.globl main
+
+main:
+	la s0, a
+	la s1, b
+	la s2, c
+	li s3, 5
+
+loop:
+	beqz s3, done
+
+	lw a0, 0(s0)
+	lw a1, 0(s1)
+
+	jal ra, sdiv
+
+	sw a0, 0(s2)
+
+	addi s0, s0, 4
+	addi s1, s1, 4
+	addi s2, s2, 4
+	addi s3, s3, -1
+
+	j loop
+
+done:
+	li a7, 10
+	ecall
+
+sdiv:
+	beqz a1, sdiv_zero
+
+	li t2, 0
+
+	slt t3, a0, x0
+	beqz t3, sdiv_skip_neg_a
+	sub a0, x0, a0
+	xori t2, t2, 1
+
+sdiv_skip_neg_a:
+	slt t3, a1, x0
+	beqz t3, sdiv_skip_neg_b
+	sub a1, x0, a1
+	xori t2, t2, 1
+
+sdiv_skip_neg_b:
+	li t4, 0
+
+sdiv_loop:
+	blt a0, a1, sdiv_done
+	sub a0, a0, a1
+	addi t4, t4, 1
+	j sdiv_loop
+
+sdiv_done:
+	mv a0, t4
+
+	beqz t2, sdiv_ret
+	sub a0, x0, a0
+
+sdiv_ret:
+	jr ra
+
+sdiv_zero:
+	li a0, 0
+	jr ra