doc: update appendix and overview

Signed-off-by: Huaqi Fang <[email protected]>

source/appendix.rst

@@ -3,26 +3,45 @@
 Appendix
 ========
 
-* **Nuclei RISC-V IP Products**: https://www.nucleisys.com/product.php
+* **Nuclei Tools and Documents**: https://nucleisys.com/download.php
 
-* **Nuclei Spec Documentation**: https://nucleisys.com/download.php#spec
+* **Nuclei Software Opensource Organization**: https://github.com/Nuclei-Software
 
-* **Nuclei RISCV Tools and Documents**: https://nucleisys.com/download.php
+* **RISC-V MCU Opensource Organization**: https://github.com/riscv-mcu
 
-* **Nuclei Prebuilt Toolchain and IDE**: https://nucleisys.com/download.php#tools
+* **Nuclei Toolchain Repo**: https://github.com/riscv-mcu/riscv-gnu-toolchain
 
-* **NMSIS**: https://github.com/Nuclei-Software/NMSIS
+* **Nuclei OpenOCD Repo**: https://github.com/riscv-mcu/riscv-openocd
 
-* **Nuclei SDK**: https://github.com/Nuclei-Software/nuclei-sdk
+* **Nuclei QEMU Repo**: https://github.com/riscv-mcu/qemu
 
-* **Nuclei Linux SDK**: https://github.com/Nuclei-Software/nuclei-linux-sdk
+* **Nuclei SDK**: https://github.com/Nuclei-Software/nuclei-sdk
 
-* **Nuclei Software Organization in Github**: https://github.com/Nuclei-Software/
+* **NMSIS**: https://github.com/Nuclei-Software/NMSIS
 
-* **RISC-V MCU Organization in Github**: https://github.com/riscv-mcu/
+* **Nuclei RISC-V IP Products**: https://www.nucleisys.com/product.php
 
 * **RISC-V MCU Community Website**: https://www.riscv-mcu.com/
 
-* **Nuclei riscv-openocd**: https://github.com/riscv-mcu/riscv-openocd
+* **Nuclei RISC-V CPU Spec**: https://doc.nucleisys.com/nuclei_spec
+
+* **RISC-V ELF psABI Document**: https://github.com/riscv-non-isa/riscv-elf-psabi-doc#navigation
+
+* **RISC-V ISA Specfications(Ratified)**: https://riscv.org/technical/specifications
+
+* **RISC-V Architecture Profiles**: https://github.com/riscv/riscv-profiles
+
+* **RISC-V Bitmanip(B) Extension Spec**: https://github.com/riscv/riscv-bitmanip
+
+* **RISC-V Packed SIMD(P) Extension Spec**: https://github.com/riscv/riscv-p-spec
+
+* **RISC-V Cryptography(K) Extension Spec**: https://github.com/riscv/riscv-crypto
+
+* **RISC-V Vector(V) Extension Spec**: https://github.com/riscv/riscv-v-spec
+
+* **RISC-V Vector Intrinsic API Spec**: https://github.com/riscv-non-isa/rvv-intrinsic-doc
+
+* **RISC-V ISA Extension Spec Status**: https://wiki.riscv.org/display/HOME/Specification+Status
+
+* **Nuclei Bumblebee Core Document**: https://github.com/nucleisys/Bumblebee_Core_Doc
 
-* **Nuclei riscv-gnu-toolchain**: https://github.com/riscv-mcu/riscv-gnu-toolchain

source/overview/intro.rst

@@ -4,19 +4,19 @@ Introduction
 ============
 
 This user guide mainly talked about how to use Nuclei Development Tools, including
-Nuclei Studio IDE, Nuclei GNU Toolchain, Nuclei OpenOCD and Nuclei QEMU.
+Nuclei Studio IDE, Nuclei RISC-V Toolchain, Nuclei OpenOCD and Nuclei QEMU.
 
-Nuclei Studio IDE is built on Eclipse Embdded CDT plugins, mainly optimized for
+**Nuclei Studio IDE** is built on Eclipse Embdded CDT plugins, mainly optimized for
 Nuclei RISC-V Processor to improve user experience in IDE.
 
-Nuclei GNU Toolchain is built on RISC-V GNU toolchain(gcc/binutils/gdb/newlib) and
-also include Nuclei C Runtime Library, it provide good support for NUclei RISC-V
+**Nuclei RISC-V Toolchain** is built on RISC-V GNU and LLVM toolchain(gcc/llvm/binutils/gdb/newlib) and
+also include Nuclei C Runtime Library, it provide good support for Nuclei RISC-V
 Processor.
 
-Nuclei OpenOCD is built on RISC-V OpenOCD, adding nuspi flash support, cjtag support,
+**Nuclei OpenOCD** is built on RISC-V OpenOCD, adding nuspi flash support, cjtag support,
 customized csr support, nuclei openocd flashloader support.
 
-Nuclei QEMU is built on QEMU project, adding Nuclei N/NX/UX RISC-V processor support,
+**Nuclei QEMU** is built on QEMU project, adding Nuclei N/NX/UX RISC-V processor support,
 which works with Nuclei SDK and Nuclei Linux SDK.
 
 .. note::