Added sio_handler

src/sio.s

@@ -0,0 +1,94 @@
+.extern sio_handler_callback
+.extern sio_handler
+
+sio_handler:
+	addi $sp, -120
+.set noat
+	sw $at, 0($sp)
+	mfhi $at
+	sw $at, 112($sp)
+	mflo $at
+	sw $at, 116($sp)
+.set at
+	sw $v0, 4($sp)
+	sw $v1, 8($sp)
+	sw $a0, 12($sp)
+	sw $a1, 16($sp)
+	sw $a2, 20($sp)
+	sw $a3, 24($sp)
+	sw $t0, 28($sp)
+	sw $t1, 32($sp)
+	sw $t2, 36($sp)
+	sw $t3, 40($sp)
+	sw $t4, 44($sp)
+	sw $t5, 48($sp)
+	sw $t6, 52($sp)
+	sw $t7, 56($sp)
+	sw $s0, 60($sp)
+	sw $s1, 64($sp)
+	sw $s2, 68($sp)
+	sw $s3, 72($sp)
+	sw $s4, 76($sp)
+	sw $s5, 80($sp)
+	sw $s6, 84($sp)
+	sw $s7, 88($sp)
+	sw $t8, 92($sp)
+	sw $t9, 96($sp)
+	sw $gp, 100($sp)
+	sw $s8, 104($sp)
+
+	la $t0, sio_handler_callback
+	lw $t1, 0($t0)
+
+	addiu $sp, $sp, -24
+	jalr $t1
+	nop
+	addiu $sp, $sp, 24
+
+	li $t0, 0x1f801070 # IPENDING
+
+	lw $t1, 0($t0)
+	nop
+	nop
+	xori $t1, $t1, 0x100 # Acknowledge SIO IRQ
+	sw $t1, 0($t0)
+
+.set noat
+	lw $at, 112($sp)
+	nop
+	mthi $at
+	lw $at, 116($sp)
+	nop
+	mtlo $at
+	lw $at, 0($sp)
+.set at
+	lw $v0, 4($sp)
+	lw $v1, 8($sp)
+	lw $a0, 12($sp)
+	lw $a1, 16($sp)
+	lw $a2, 20($sp)
+	lw $a3, 24($sp)
+	lw $t0, 28($sp)
+	lw $t1, 32($sp)
+	lw $t2, 36($sp)
+	lw $t3, 40($sp)
+	lw $t4, 44($sp)
+	lw $t5, 48($sp)
+	lw $t6, 52($sp)
+	lw $t7, 56($sp)
+	lw $s0, 60($sp)
+	lw $s1, 64($sp)
+	lw $s2, 68($sp)
+	lw $s3, 72($sp)
+	lw $s4, 76($sp)
+	lw $s5, 80($sp)
+	lw $s6, 84($sp)
+	lw $s7, 88($sp)
+	lw $t8, 92($sp)
+	lw $t9, 96($sp)
+	lw $gp, 100($sp)
+	lw $s8, 104($sp)
+	lw $ra, 108($sp)
+	addi $sp, 120
+	jr $ra
+	nop