From 943f45dcc3cc8bba853256ed6c2b58adea738d09 Mon Sep 17 00:00:00 2001
From: bx <bx@tilde.town>
Date: Tue, 31 Aug 2021 22:22:29 +0100
Subject: [PATCH] got printf working with static string!

---
 assembler.rb | 52 ++++++++++++++++++++++++++++++++++++++--------------
 1 file changed, 38 insertions(+), 14 deletions(-)

diff --git a/assembler.rb b/assembler.rb
index 8c5a10d..4173c14 100644
--- a/assembler.rb
+++ b/assembler.rb
@@ -16,6 +16,7 @@ end
 
 def string(s)
 	$bytes.push *s.bytes
+	$bytes.push 0 # null terminate
 	while (($bytes.length % 4) != 0) do
 		$bytes.push 0
 	end
@@ -141,6 +142,15 @@ def addi(src, val, dest)
 	word op
 end
 
+# jump register
+def jr(reg)
+	#      oooooo rrrrr ----- ----- ----- oooooo
+	op = 0b000000_00000_00000_00000_00000_001000
+	op |= (reg & 0b11111) << 21
+	word op
+end
+
+
 
 # # # PSEUDO-INSTRUCTIONS # # #
 def nop
@@ -199,9 +209,33 @@ $bytes = []
 
 # # # PROGRAM CODE # # #
 nop
+jmp $base_addr + 0x400
+nop
+
+l_hello_world = label
+string "ello wrld!\n"
+
+
+
+l_printf = label
+addiu r0, 0xa0, at # address of bios func
+jr at
+addiu r0, 0x3f, t1 # printf number
+
+
+
+zero_fill 0x400 - 1
+nop
+
+
+
+lwi l_hello_world, a0
+jal l_printf
+addiu sp, -16, sp # delay slot
+addiu sp, 16, sp
+
+nop ; nop ; nop ; nop
 
-# ops should always be in format of
-# src [args] -> dest
 
 # THIS IS NEEDED
 lwi $gp1, t0
@@ -239,19 +273,9 @@ nop ; nop ; nop ; nop
 nop ; nop ; nop ; nop
 
 l_end_loop = label
-
-addiu r0, -10, t3
-#addiu t3, 6, t3
-addiu t3, -10, t3
 nop
-
-addi r0, -10, t4
-#addi t4, 6, t4
-addi t4, -10, t4
-nop
-
-nop
-jmp l_end_loop
+lwi l_end_loop, t9
+jr t9
 nop