https://salsa.debian.org/firebird-team/firebird3.0/-/raw/master/debian/patches/upstream/riscv64-support.patch

1e8e7858db84750a77006d307bf28e9686f9414e Patch for CORE-5779: support for riscv64, also some code fixes related with prior ports
 Minor corrections compared to the commit above due to whitespace/spelling
 differences with 3.0 version
Bug-Debian: https://bugs.debian.org/895257
Bug: http://tracker.firebirdsql.org/browse/CORE-5779

--- a/configure.ac
+++ b/configure.ac
@@ -251,6 +251,18 @@ dnl CPU_TYPE=ppc64
     libdir=/usr/lib64
     ;;
 
+  riscv64*-*-linux*)
+    MAKEFILE_PREFIX=linux_riscv64
+    INSTALL_PREFIX=linux
+    PLATFORM=LINUX
+    AC_DEFINE(LINUX, 1, [Define this if OS is Linux])
+    EDITLINE_FLG=Y
+    SHRLIB_EXT=so
+    STD_EDITLINE=true
+    STD_ICU=true
+    libdir=/usr/lib64
+    ;;
+
   powerpc64le-*-linux*)
     MAKEFILE_PREFIX=linux_powerpc64el
     INSTALL_PREFIX=linux
--- a/src/common/classes/DbImplementation.cpp
+++ b/src/common/classes/DbImplementation.cpp
@@ -49,6 +49,7 @@ static const UCHAR CpuAlpha = 14;
 static const UCHAR CpuArm64 = 15;
 static const UCHAR CpuPowerPc64el = 16;
 static const UCHAR CpuM68k = 17;
+static const UCHAR CpuRiscV64 = 18;
 
 static const UCHAR OsWindows = 0;
 static const UCHAR OsLinux = 1;
@@ -89,7 +90,8 @@ const char* hardware[] = {
 	"Alpha",
 	"ARM64",
 	"PowerPC64el",
-	"M68k"
+	"M68k",
+	"RiscV64"
 };
 
 const char* operatingSystem[] = {
@@ -116,22 +118,22 @@ const char* compiler[] = {
 // This table lists pre-fb3 implementation codes
 const UCHAR backwardTable[FB_NELEM(hardware) * FB_NELEM(operatingSystem)] =
 {
-//				Intel	AMD		Sparc	PPC		PPC64	MIPSEL	MIPS	ARM		IA64	s390	s390x	SH		SHEB	HPPA	Alpha	ARM64	PowerPC64el
-/* Windows */	50,		68,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,
-/* Linux */		60,		66,		65,		69,		86,		71,		72,		75, 	76,		79, 	78,		80,		81,		82,		83,		84,		85,
-/* Darwin */	70,		73,		0,		63,		77,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,
-/* Solaris */	0,		0,		30,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,
-/* HPUX */		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,		31,		0,		0,		0,
-/* AIX */			0,		0,		0,		35,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,
-/* MVS */			0,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,
-/* FreeBSD */	61,		67,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,
-/* NetBSD */	62,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0
+//				Intel	AMD		Sparc	PPC		PPC64	MIPSEL	MIPS	ARM		IA64	s390	s390x	SH		SHEB	HPPA	Alpha	ARM64	PPC64el	M68k	RiscV64
+/* Windows */	50,		68,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,
+/* Linux */		60,		66,		65,		69,		86,		71,		72,		75, 	76,		79, 	78,		80,		81,		82,		83,		84,		85,		87,		88,
+/* Darwin */	70,		73,		0,		63,		77,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,
+/* Solaris */	0,		0,		30,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,
+/* HPUX */		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,		31,		0,		0,		0,		0,		0,
+/* AIX */		0,		0,		0,		35,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,
+/* MVS */		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,
+/* FreeBSD */	61,		67,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,
+/* NetBSD */	62,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0,		0
 };
 
 const UCHAR backEndianess[FB_NELEM(hardware)] =
 {
-//	Intel	AMD		Sparc	PPC		PPC64	MIPSEL	MIPS	ARM		IA64	s390	s390x	SH		SHEB	HPPA	Alpha	ARM64	PowerPC64el	M68k
-	0,		0,		1,		1,		1,		0,		1,		0,		0,		1,		1,		0,		1,		1,		0,		0,		0,		1
+//	Intel	AMD		Sparc	PPC		PPC64	MIPSEL	MIPS	ARM		IA64	s390	s390x	SH		SHEB	HPPA	Alpha	ARM64	PPC64el	M68k	RiscV64
+	0,		0,		1,		1,		1,		0,		1,		0,		0,		1,		1,		0,		1,		1,		0,		0,		0,		1,		0,
 };
 
 } // anonymous namespace
--- a/src/common/common.h
+++ b/src/common/common.h
@@ -135,6 +135,10 @@
 #define FB_CPU CpuArm64
 #endif /* ARM64 */
 
+#ifdef RISCV64
+#define FB_CPU CpuRiscV64
+#endif /* RISCV64 */
+
 #ifdef sparc
 #define FB_CPU CpuUltraSparc
 #define RISC_ALIGNMENT
--- a/src/jrd/inf_pub.h
+++ b/src/jrd/inf_pub.h
@@ -247,7 +247,7 @@ enum  info_db_implementations
 	isc_info_db_impl_linux_ppc64el = 85,
 	isc_info_db_impl_linux_ppc64 = 86,
 	isc_info_db_impl_linux_m68k = 87,
-
+	isc_info_db_impl_linux_riscv64 = 88,
 
 	isc_info_db_impl_last_value   // Leave this LAST!
 };