使用MIPS汇编器和C语言开发PS1游戏

国外课程，有字幕

使用MIPS汇编器和C语言开发PS1游戏
├──001. Starting our Journey.mp4 101.92M
├──001. Starting our Journey.srt 17.08kb
├──002. How to Take this Course.mp4 4.32M
├──002. How to Take this Course.srt 3.86kb
├──002. How to Take this Course.vtt 4.14kb
├──003. Placing the PlayStation in History.mp4 90.94M
├──003. Placing the PlayStation in History.srt 14.26kb
├──003. Placing the PlayStation in History.vtt 15.07kb
├──004. PS1 Hardware Overview.srt 20.13kb
├──004. PS1 Hardware Overview.vtt 21.52kb
├──005. The MIPS CPU.mp4 43.08M
├──005. The MIPS CPU.srt 13.59kb
├──005. The MIPS CPU.vtt 14.57kb
├──006. Memory & Endianness.mp4 30.97M
├──006. Memory & Endianness.srt 9.97kb
├──006. Memory & Endianness.vtt 10.75kb
├──007. Memory Map.mp4 30.66M
├──007. Memory Map.srt 17.02kb
├──007. Memory Map.vtt 17.94kb
├──008. CPU Registers & Load Instructions.mp4 81.32M
├──008. CPU Registers & Load Instructions.srt 20.72kb
├──009. Store, Add, & Subtract Instructions.mp4 42.22M
├──009. Store, Add, & Subtract Instructions.srt 9.80kb
├──009. Store, Add, & Subtract Instructions.vtt 10.18kb
├──010. Jump & Branch Instructions.mp4 35.06M
├──010. Jump & Branch Instructions.srt 11.05kb
├──010. Jump & Branch Instructions.vtt 11.09kb
├──011. Exercise Our First MIPS Code.mp4 18.45M
├──011. Exercise Our First MIPS Code.srt 4.16kb
├──011. Exercise Our First MIPS Code.vtt 4.29kb
├──012. Going Over Our First MIPS Code.mp4 26.29M
├──012. Going Over Our First MIPS Code.srt 6.58kb
├──012. Going Over Our First MIPS Code.vtt 6.57kb
├──013. Installing the ARMIPS Assembler.mp4 34.70M
├──013. Installing the ARMIPS Assembler.vtt 8.57kb
├──014. Assembling our MIPS Code.mp4 7.40M
├──014. Assembling our MIPS Code.srt 6.28kb
├──014. Assembling our MIPS Code.vtt 6.29kb
├──015. PSX-EXE File Format.srt 5.46kb
├──015. PSX-EXE File Format.vtt 5.48kb
├──016. Emulator & Step-By-Step Execution.mp4 33.02M
├──016. Emulator & Step-By-Step Execution.srt 9.56kb
├──016. Emulator & Step-By-Step Execution.vtt 9.62kb
├──017. Fixing Off-By-One Error.mp4 10.29M
├──017. Fixing Off-By-One Error.vtt 4.58kb
├──018. Pseudo-Instructions.mp4 34.24M
├──018. Pseudo-Instructions.srt 10.19kb
├──018. Pseudo-Instructions.vtt 10.69kb
├──019. The MIPS Pipeline.mp4 66.19M
├──019. The MIPS Pipeline.vtt 15.22kb
├──020. Some Warm Up Exercises.mp4 17.43M
├──020. Some Warm Up Exercises.srt 9.48kb
├──020. Some Warm Up Exercises.vtt 10.22kb
├──021. Solving our Warm Up Exercises.mp4 43.22M
├──021. Solving our Warm Up Exercises.srt 20.37kb
├──022. Register Shorthand.mp4 22.98M
├──022. Register Shorthand.srt 6.66kb
├──022. Register Shorthand.vtt 7.06kb
├──023. Factorial Exercise.mp4 24.59M
├──023. Factorial Exercise.srt 7.30kb
├──023. Factorial Exercise.vtt 7.68kb
├──024. Solving our Factorial Exercise.mp4 40.56M
├──024. Solving our Factorial Exercise.srt 11.88kb
├──024. Solving our Factorial Exercise.vtt 12.13kb
├──025. Factorial Subroutine.mp4 40.00M
├──025. Factorial Subroutine.srt 13.63kb
├──025. Factorial Subroutine.vtt 14.22kb
├──026. Negative Numbers.mp4 40.79M
├──026. Negative Numbers.srt 16.02kb
├──026. Negative Numbers.vtt 16.85kb
├──027. Sign Extension.mp4 29.87M
├──027. Sign Extension.srt 9.58kb
├──027. Sign Extension.vtt 10.09kb
├──028. Logical Instructions.mp4 28.28M
├──028. Logical Instructions.srt 8.91kb
├──029. Bitshifting Instructions.mp4 32.14M
├──029. Bitshifting Instructions.srt 13.01kb
├──029. Bitshifting Instructions.vtt 14.04kb
├──030. Examples of CISC & RISC Machines.mp4 38.67M
├──030. Examples of CISC & RISC Machines.srt 8.99kb
├──030. Examples of CISC & RISC Machines.vtt 9.33kb
├──031. CISC vs RISC Instructions.mp4 81.97M
├──031. CISC vs RISC Instructions.srt 23.06kb
├──032. The PlayStation Graphics System.mp4 77.40M
├──032. The PlayStation Graphics System.vtt 25.42kb
├──033. Drawing Primitives.mp4 36.17M
├──033. Drawing Primitives.vtt 8.06kb
├──034. GPU Packets.mp4 66.17M
├──034. GPU Packets.srt 17.17kb
├──035. Sending Display Control Packets to GP1.mp4 81.47M
├──035. Sending Display Control Packets to GP1.srt 25.13kb
├──035. Sending Display Control Packets to GP1.vtt 26.08kb
├──036. Sending VRAM Access Packets to GP0.mp4 33.16M
├──036. Sending VRAM Access Packets to GP0.srt 9.84kb
├──036. Sending VRAM Access Packets to GP0.vtt 10.20kb
├──037. Clear Display Area.mp4 26.87M
├──037. Clear Display Area.srt 9.40kb
├──037. Clear Display Area.vtt 9.34kb
├──038. Drawing a Flat-Shaded Triangle.mp4 18.31M
├──038. Drawing a Flat-Shaded Triangle.srt 6.57kb
├──038. Drawing a Flat-Shaded Triangle.vtt 6.48kb
├──039. Drawing a Flat-Shaded Quad.mp4 11.84M
├──039. Drawing a Flat-Shaded Quad.srt 3.97kb
├──039. Drawing a Flat-Shaded Quad.vtt 3.85kb
├──040. Drawing a Gouraud-Shaded Triangle.mp4 9.21M
├──040. Drawing a Gouraud-Shaded Triangle.srt 2.50kb
├──040. Drawing a Gouraud-Shaded Triangle.vtt 2.51kb
├──041. Flat-Shaded Triangle Subroutine.mp4 49.37M
├──041. Flat-Shaded Triangle Subroutine.srt 18.01kb
├──041. Flat-Shaded Triangle Subroutine.vtt 18.34kb
├──042. Coding our Flat Triangle Subroutine.mp4 19.81M
├──042. Coding our Flat Triangle Subroutine.srt 6.43kb
├──042. Coding our Flat Triangle Subroutine.vtt 6.50kb
├──043. Stack & Stack Pointer.mp4 42.51M
├──043. Stack & Stack Pointer.srt 15.35kb
├──043. Stack & Stack Pointer.vtt 15.97kb
├──044. Stack Parameters.mp4 24.55M
├──044. Stack Parameters.srt 9.65kb
├──044. Stack Parameters.vtt 9.93kb
├──045. Stack & Heap Space.mp4 39.42M
├──045. Stack & Heap Space.srt 7.49kb
├──045. Stack & Heap Space.vtt 7.85kb
├──046. Variables.srt 11.72kb
├──047. Variable Alignment.mp4 20.15M
├──047. Variable Alignment.srt 9.98kb
├──047. Variable Alignment.vtt 10.34kb
├──048. Vector Alignment.mp4 62.64M
├──048. Vector Alignment.srt 18.90kb
├──048. Vector Alignment.vtt 19.63kb
├──049. Copying Image Data to VRAM.mp4 103.38M
├──049. Copying Image Data to VRAM.srt 30.46kb
├──049. Copying Image Data to VRAM.vtt 31.55kb
├──050. Using Bitshifting to Multiply & Divide.mp4 32.99M
├──050. Using Bitshifting to Multiply & Divide.vtt 9.74kb
├──051. 24BPP Display Mode.mp4 59.12M
├──051. 24BPP Display Mode.srt 18.77kb
├──051. 24BPP Display Mode.vtt 19.07kb
├──052. Taking Advantage of our Delay Slots.mp4 28.78M
├──052. Taking Advantage of our Delay Slots.srt 8.53kb
├──052. Taking Advantage of our Delay Slots.vtt 8.77kb
├──053. Moving from MIPS Assembly to C.mp4 25.86M
├──053. Moving from MIPS Assembly to C.srt 8.36kb
├──053. Moving from MIPS Assembly to C.vtt 8.89kb
├──054. Installing Tools on Windows 11.mp4 46.54M
├──054. Installing Tools on Windows 11.srt 20.26kb
├──054. Installing Tools on Windows 11.vtt 20.83kb
├──055. Installing Tools on Windows XP.mp4 66.76M
├──055. Installing Tools on Windows XP.srt 29.08kb
├──055. Installing Tools on Windows XP.vtt 30.54kb
├──056. Compiling a Simple Psy-Q Project.mp4 33.98M
├──056. Compiling a Simple Psy-Q Project.vtt 17.12kb
├──057. Double-Buffer Screen.srt 39.35kb
├──057. Double-Buffer Screen.vtt 40.91kb
├──058. Psy-Q Integer Data Types.mp4 14.25M
├──058. Psy-Q Integer Data Types.srt 5.38kb
├──058. Psy-Q Integer Data Types.vtt 5.50kb
├──059. Psy-Q Primitive Types.srt 10.62kb
├──059. Psy-Q Primitive Types.vtt 10.73kb
├──060. Ordering Table & Primitive Buffer.mp4 61.83M
├──060. Ordering Table & Primitive Buffer.srt 26.27kb
├──060. Ordering Table & Primitive Buffer.vtt 27.35kb
├──061. Sorting Primitives into the OT.mp4 47.86M
├──061. Sorting Primitives into the OT.srt 22.01kb
├──061. Sorting Primitives into the OT.vtt 22.32kb
├──062. Sorting a Gouraud Quad into the OT.mp4 25.12M
├──062. Sorting a Gouraud Quad into the OT.srt 8.21kb
├──063. A Review of Pointers.mp4 64.45M
├──063. A Review of Pointers.srt 18.50kb
├──064. The Arrow Operator.srt 17.02kb
├──065. A Review of 3D Projection.srt 24.19kb
├──065. A Review of 3D Projection.vtt 25.47kb
├──066. Vertices & Face Indices.mp4 52.57M
├──066. Vertices & Face Indices.vtt 18.89kb
├──067. The Geometry Transformation Engine.mp4 19.92M
├──067. The Geometry Transformation Engine.srt 10.63kb
├──067. The Geometry Transformation Engine.vtt 11.54kb
├──068. Basic 3D Transformations.mp4 45.86M
├──068. Basic 3D Transformations.srt 15.76kb
├──068. Basic 3D Transformations.vtt 16.53kb
├──069. RotTransPers Function.mp4 70.44M
├──069. RotTransPers Function.srt 23.36kb
├──069. RotTransPers Function.vtt 24.84kb
├──070. Coding a Rotating 3D Cube.mp4 54.98M
├──070. Coding a Rotating 3D Cube.srt 20.80kb
├──070. Coding a Rotating 3D Cube.vtt 21.61kb
├──071. Normal Clip.mp4 26.15M
├──071. Normal Clip.vtt 9.67kb
├──072. Coding Quads as Cube Faces.mp4 12.56M
├──072. Coding Quads as Cube Faces.srt 4.60kb
├──072. Coding Quads as Cube Faces.vtt 4.53kb
├──073. Reviewing Floating-Point Numbers.srt 21.86kb
├──073. Reviewing Floating-Point Numbers.vtt 23.74kb
├──074. Fixed-Point Numbers.mp4 48.52M
├──074. Fixed-Point Numbers.srt 21.86kb
├──074. Fixed-Point Numbers.vtt 24.07kb
├──075. Implementing a Bouncing Cube.mp4 52.08M
├──075. Implementing a Bouncing Cube.srt 15.23kb
├──075. Implementing a Bouncing Cube.vtt 16.18kb
├──076. Different Transform Matrix per Object.mp4 60.67M
├──076. Different Transform Matrix per Object.vtt 25.26kb
├──077. Wait, Can I use Floats.mp4 6.12M
├──077. Wait, Can I use Floats.srt 3.58kb
├──077. Wait, Can I use Floats.vtt 3.73kb
├──078. GTE Register Set.mp4 38.56M
├──078. GTE Register Set.srt 14.08kb
├──078. GTE Register Set.vtt 15.11kb
├──079. Inline GTE Instructions.mp4 62.87M
├──079. Inline GTE Instructions.srt 20.55kb
├──079. Inline GTE Instructions.vtt 21.22kb
├──080. RTPT vs. RTPS.mp4 34.35M
├──080. RTPT vs. RTPS.srt 10.80kb
├──080. RTPT vs. RTPS.vtt 11.10kb
├──081. Reading Joypad State.mp4 65.96M
├──081. Reading Joypad State.srt 25.99kb
├──081. Reading Joypad State.vtt 27.44kb
├──082. Joypad Input with BIOS Functions.mp4 79.94M
├──082. Joypad Input with BIOS Functions.srt 25.27kb
├──082. Joypad Input with BIOS Functions.vtt 25.35kb
├──083. Joypad Header & Implementation.mp4 90.43M
├──083. Joypad Header & Implementation.srt 29.34kb
├──083. Joypad Header & Implementation.vtt 30.29kb
├──084. Header File for OT & Primitive Buffer.mp4 79.70M
├──084. Header File for OT & Primitive Buffer.srt 33.71kb
├──085. Header File for Display Routines.mp4 25.82M
├──085. Header File for Display Routines.srt 8.76kb
├──086. Camera Space.mp4 54.80M
├──086. Camera Space.srt 15.93kb
├──086. Camera Space.vtt 17.04kb
├──087. The Look-At Transformation.mp4 73.91M
├──087. The Look-At Transformation.srt 22.37kb
├──088. The LookAt Function.mp4 66.73M
├──088. The LookAt Function.srt 22.72kb
├──088. The LookAt Function.vtt 24.81kb
├──089. Coding the Look-At Camera Model.mp4 83.63M
├──089. Coding the Look-At Camera Model.srt 26.26kb
├──089. Coding the Look-At Camera Model.vtt 27.29kb
├──090. CD-ROM Basics.mp4 65.21M
├──090. CD-ROM Basics.vtt 30.44kb
├──091. Generating an ISO on Windows XP.srt 19.48kb
├──091. Generating an ISO on Windows XP.vtt 19.91kb
├──092. Generating an ISO on Windows 11.mp4 32.70M
├──092. Generating an ISO on Windows 11.srt 11.28kb
├──092. Generating an ISO on Windows 11.vtt 11.29kb
├──093. A Function to Read Files from the CD.mp4 93.63M
├──093. A Function to Read Files from the CD.srt 29.01kb
├──093. A Function to Read Files from the CD.vtt 30.11kb
├──094. Understanding the MODEL.BIN File.mp4 23.87M
├──094. Understanding the MODEL.BIN File.srt 9.78kb
├──094. Understanding the MODEL.BIN File.vtt 10.03kb
├──095. Dynamically Allocating Buffers.mp4 49.81M
├──095. Dynamically Allocating Buffers.srt 12.02kb
├──095. Dynamically Allocating Buffers.vtt 12.36kb
├──096. Heap Initialization on Windows 11.srt 8.35kb
├──097. Interpreting Bytes as Numbers.mp4 72.29M
├──097. Interpreting Bytes as Numbers.srt 20.16kb
├──097. Interpreting Bytes as Numbers.vtt 20.59kb
├──098. Handling Different Order of Bytes.mp4 47.08M
├──098. Handling Different Order of Bytes.srt 12.70kb
├──098. Handling Different Order of Bytes.vtt 12.91kb
├──099. Reading Vertices & Faces from a File.mp4 51.18M
├──099. Reading Vertices & Faces from a File.srt 18.58kb
├──099. Reading Vertices & Faces from a File.vtt 19.00kb
├──100. UV Coordinates, TPAGE, & CLUT.mp4 61.13M
├──100. UV Coordinates, TPAGE, & CLUT.srt 23.34kb
├──100. UV Coordinates, TPAGE, & CLUT.vtt 24.72kb
├──101. Installing TIM Tool.mp4 7.65M
├──101. Installing TIM Tool.srt 4.87kb
├──101. Installing TIM Tool.vtt 4.98kb
├──102. TIM File Format.mp4 25.85M
├──102. TIM File Format.vtt 15.26kb
├──103. Read TIM File from the CD.mp4 75.61M
├──103. Read TIM File from the CD.srt 27.47kb
├──103. Read TIM File from the CD.vtt 27.88kb
├──104. Textured Cube Faces.srt 23.04kb
├──104. Textured Cube Faces.vtt 23.60kb
├──105. Wobbly Textures.mp4 100.18M
├──105. Wobbly Textures.srt 15.62kb
├──105. Wobbly Textures.vtt 16.68kb
├──106. Polygon Jitter.mp4 8.73M
├──106. Polygon Jitter.srt 3.62kb
├──106. Polygon Jitter.vtt 3.91kb
├──107. Dev Tools CD Samples.mp4 41.19M
├──107. Dev Tools CD Samples.srt 11.02kb
├──107. Dev Tools CD Samples.vtt 11.38kb
├──108. Intro to our Final Project.mp4 80.92M
├──108. Intro to our Final Project.srt 13.68kb
├──109. Importing Project Assets.mp4 9.21M
├──109. Importing Project Assets.srt 5.44kb
├──110. PRM File Layout.mp4 49.00M
├──110. PRM File Layout.srt 17.92kb
├──110. PRM File Layout.vtt 18.57kb
├──111. Reading Object Name from PRM File.mp4 55.21M
├──111. Reading Object Name from PRM File.srt 18.42kb
├──111. Reading Object Name from PRM File.vtt 19.19kb
├──112. Reading Vertices from PRM File.mp4 41.33M
├──112. Reading Vertices from PRM File.vtt 15.77kb
├──113. Handling Different Primitive Types.mp4 103.01M
├──113. Handling Different Primitive Types.srt 24.86kb
├──113. Handling Different Primitive Types.vtt 25.78kb
├──114. Reading Primitives from PRM File.mp4 58.35M
├──114. Reading Primitives from PRM File.srt 17.81kb
├──114. Reading Primitives from PRM File.vtt 18.32kb
├──115. Drawing Flat-Shaded Object Faces.mp4 103.84M
├──115. Drawing Flat-Shaded Object Faces.srt 33.40kb
├──116. Using sizeof with Variable Name.mp4 11.47M
├──116. Using sizeof with Variable Name.srt 3.37kb
├──116. Using sizeof with Variable Name.vtt 3.58kb
├──117. CMP File Layout.mp4 68.74M
├──117. CMP File Layout.srt 15.25kb
├──117. CMP File Layout.vtt 16.17kb
├──118. Reading Number of Textures from File.mp4 29.68M
├──118. Reading Number of Textures from File.srt 8.77kb
├──118. Reading Number of Textures from File.vtt 9.07kb
├──119. Reading TIM Sizes from File.mp4 60.10M
├──119. Reading TIM Sizes from File.srt 18.22kb
├──119. Reading TIM Sizes from File.vtt 19.05kb
├──120. A Function to Extract LZSS Data.mp4 33.58M
├──120. A Function to Extract LZSS Data.srt 15.02kb
├──120. A Function to Extract LZSS Data.vtt 15.52kb
├──121. Texture Structs.mp4 47.34M
├──121. Texture Structs.srt 18.81kb
├──121. Texture Structs.vtt 20.03kb
├──122. Uploading CMP Textures to VRAM.mp4 63.00M
├──122. Uploading CMP Textures to VRAM.srt 23.75kb
├──122. Uploading CMP Textures to VRAM.vtt 24.58kb
├──123. Global Texture Store Array.mp4 75.36M
├──123. Global Texture Store Array.srt 16.80kb
├──123. Global Texture Store Array.vtt 17.39kb
├──124. Rendering Textured Triangles.srt 7.84kb
├──124. Rendering Textured Triangles.vtt 8.09kb
├──125. Visualizing Textured 3D Objects.mp4 40.50M
├──125. Visualizing Textured 3D Objects.srt 9.46kb
├──126. Loading Multiple CMP Files.mp4 59.49M
├──126. Loading Multiple CMP Files.srt 14.63kb
├──126. Loading Multiple CMP Files.vtt 15.15kb
├──127. Exercise Linked List of Objects.mp4 29.74M
├──127. Exercise Linked List of Objects.srt 10.22kb
├──127. Exercise Linked List of Objects.vtt 11.11kb
├──128. Linked List Implementation.mp4 61.49M
├──128. Linked List Implementation.vtt 22.05kb
├──129. Joypad Press & Release.mp4 8.97M
├──129. Joypad Press & Release.srt 3.54kb
├──129. Joypad Press & Release.vtt 3.60kb
├──130. Reading Scene Objects from CD.mp4 98.35M
├──130. Reading Scene Objects from CD.srt 26.99kb
├──130. Reading Scene Objects from CD.vtt 27.92kb
├──131. Camera-Object Distance Check.mp4 41.10M
├──131. Camera-Object Distance Check.srt 14.66kb
├──131. Camera-Object Distance Check.vtt 15.25kb
├──132. Drawing Scene Objects.mp4 52.01M
├──132. Drawing Scene Objects.vtt 12.64kb
├──133. Track Sections & Faces.mp4 66.24M
├──133. Track Sections & Faces.vtt 22.44kb
├──134. Structs for Sessions & Faces.mp4 23.47M
├──134. Structs for Sessions & Faces.srt 9.26kb
├──134. Structs for Sessions & Faces.vtt 9.65kb
├──135. Reading Vertices, Faces, & Sections.mp4 73.84M
├──135. Reading Vertices, Faces, & Sections.srt 27.72kb
├──136. Function to Render Track Sections.mp4 96.49M
├──136. Function to Render Track Sections.srt 28.11kb
├──136. Function to Render Track Sections.vtt 29.25kb
├──137. Shrinking Track Vertices.srt 16.94kb
├──137. Shrinking Track Vertices.vtt 17.50kb
├──138. Exercise Testing Face Flags.mp4 26.40M
├──138. Exercise Testing Face Flags.srt 6.53kb
├──138. Exercise Testing Face Flags.vtt 6.85kb
├──139. Drawing Quad Lines.mp4 28.19M
├──139. Drawing Quad Lines.srt 7.76kb
├──139. Drawing Quad Lines.vtt 7.80kb
├──140. Avoiding the GTE 16-bit Limitation.mp4 67.02M
├──140. Avoiding the GTE 16-bit Limitation.srt 15.64kb
├──140. Avoiding the GTE 16-bit Limitation.vtt 16.88kb
├──141. Clamping Overflow Values.srt 22.13kb
├──141. Clamping Overflow Values.vtt 23.31kb
├──142. Loading Track Texture Tiles.mp4 101.76M
├──142. Loading Track Texture Tiles.srt 30.96kb
├──142. Loading Track Texture Tiles.vtt 32.28kb
├──143. Manually Position Textures in VRAM.mp4 80.09M
├──143. Manually Position Textures in VRAM.vtt 20.40kb
├──144. Loading Track Face UV Coords.mp4 46.25M
├──144. Loading Track Face UV Coords.vtt 12.66kb
├──145. Flip Face Texture.mp4 25.18M
├──145. Flip Face Texture.srt 7.88kb
├──145. Flip Face Texture.vtt 7.94kb
├──146. Tessellation & Polygon Subdivision.srt 19.98kb
├──146. Tessellation & Polygon Subdivision.vtt 21.01kb
├──147. Drawing Quads Recursively.mp4 37.86M
├──147. Drawing Quads Recursively.srt 18.26kb
├──147. Drawing Quads Recursively.vtt 18.94kb
├──148. A Function to Draw Quads Recursively.mp4 75.94M
├──148. A Function to Draw Quads Recursively.srt 16.36kb
├──148. A Function to Draw Quads Recursively.vtt 17.16kb
├──149. Subdividing UV Coordinates.mp4 48.99M
├──149. Subdividing UV Coordinates.srt 14.27kb
├──149. Subdividing UV Coordinates.vtt 14.79kb
├──150. T-junctions.mp4 126.20M
├──150. T-junctions.srt 19.82kb
├──150. T-junctions.vtt 20.78kb
├──code.zip 1.14G
└──PS1 Programming with MIPS Assembly & C.txt 4.01kb