Add svcOutputDebugString

MakefileNSO

@@ -32,7 +32,7 @@ include $(DEVKITPRO)/libnx/switch_rules
 #---------------------------------------------------------------------------------
 TARGET		?=	$(notdir $(CURDIR))$(SMOVER)
 BUILD		?=	build$(SMOVER)
-SOURCES		:=  source/sead/time source/sead source/puppets source/server source/layouts source/states source/cameras source
+SOURCES		:=  source/sead/time source/sead source/puppets source/server source/layouts source/states source/cameras source/nx source
 DATA		:=	data
 INCLUDES	:=	include include/sead
 

include/nx/svc.h

@@ -0,0 +1,20 @@
+/**
+ * @file svc.h
+ * @brief Wrappers for kernel syscalls.
+ * @copyright libnx Authors
+ */
+#pragma once
+
+extern "C" {
+
+/**
+ * @brief Outputs debug text, if used during debugging.
+ * @param[in] str Text to output.
+ * @param[in] size Size of the text in bytes.
+ * @return Result code.
+ * @note Syscall number 0x27.
+ */
+Result svcOutputDebugString(const char *str, u64 size);
+
+
+}

source/nx/svc.s

@@ -0,0 +1,17 @@
+.macro SVC_BEGIN name
+	.section .text.\name, "ax", %progbits
+	.global \name
+	.type \name, %function
+	.align 2
+	.cfi_startproc
+\name:
+.endm
+
+.macro SVC_END
+	.cfi_endproc
+.endm
+
+SVC_BEGIN svcOutputDebugString
+	svc 0x27
+	ret
+SVC_END