Initial drop

Add some riscv code

Signed-off-by: Carlos Maiolino <[email protected]>

1 files changed, 39 insertions, 0 deletions

diff --git a/riscv/pow.s b/riscv/pow.s
new file mode 100644
index 0000000..8aa339d
--- /dev/null
+++ b/riscv/pow.s
@@ -0,0 +1,39 @@
+# Calculate a^b. Where: a0=a, a1=b
+#
+# Also, this is a good example of how numeric labels can be used
+#
+# Label 1: can be defined and redefined everywhere, and we can use
+# a suffix when referencing it, to specify if we want to reference
+# the previous or the next definition of the label, according to the
+# current position. 'b' for before 'f' for after.
+#
+# Ex:
+#
+# beqz	a1, 1f  # refers to the symbol 1 defined after this instruction
+#
+
+.globl _start
+.section .text
+pow:
+	mv	a2, a0
+	li	a0, 1
+
+1:
+	beqz	a1, 1f
+	mul	a0, a0, a2
+	addi	a1, a1, -1
+	j	1b
+
+1:
+	ret
+
+_start:
+	li	a0, 2
+	li	a1, 3
+	jal	pow
+
+	# Setup exit ecall
+	# Return value is already in a0
+
+	li a7, 93
+	ecall