From 2e9bb3fd76b53268bb2d24539037c6ed2cbbdf1e Mon Sep 17 00:00:00 2001
From: Konstantin Nazarov <mail@knazarov.com>
Date: Sat, 21 Dec 2024 20:51:52 +0000
Subject: [PATCH] Better memory errors and in general more runtime memory

---
 src/elf.cpp |  4 +++-
 src/rve.cpp |  2 +-
 src/vm.cpp  | 24 ++++++++++++++++--------
 3 files changed, 20 insertions(+), 10 deletions(-)

diff --git a/src/elf.cpp b/src/elf.cpp
index 1b13a4e..cf105cd 100644
--- a/src/elf.cpp
+++ b/src/elf.cpp
@@ -158,7 +158,9 @@ std::vector<uint8_t> load_elf(const std::string& filename, size_t memory_size) {
   for (const Elf32Section& shdr : sectionHeaders) {
     if (should_load_section(shdr)) {
       if (shdr.sh_type == SHT_NOBITS) {
-        throw std::runtime_error("Trying to load section without data");
+        // Section contains no data - just skip it. It will be initialized
+        // to zero.
+        continue;
       }
 
       file.seekg(shdr.sh_offset);
diff --git a/src/rve.cpp b/src/rve.cpp
index 2e614f4..1190220 100644
--- a/src/rve.cpp
+++ b/src/rve.cpp
@@ -10,7 +10,7 @@
 #include "vm.hpp"
 
 int main(int argc, char *argv[]) {
-  const size_t MEMORY_SIZE = 512 * 1024;
+  const size_t MEMORY_SIZE = 64 * 1024 * 1024;
 
   bool debug = false;
   std::string program_filename = "";
diff --git a/src/vm.cpp b/src/vm.cpp
index df31cf3..9b8b10f 100644
--- a/src/vm.cpp
+++ b/src/vm.cpp
@@ -32,7 +32,8 @@ void VM::setreg(size_t regnum, uint32_t value) {
 
 void UART::read_mem_u8(uint8_t* dst, size_t addr) {
   if (addr < UART_ADDR || addr + 1 > UART_ADDR + 8) {
-    throw std::runtime_error("Memory access out of bounds");
+    throw std::runtime_error(std::string("Memory access out of bounds: ") +
+                             std::format("{:x}", addr));
   }
   addr -= UART_ADDR;
   switch (addr) {
@@ -46,7 +47,8 @@ void UART::read_mem_u8(uint8_t* dst, size_t addr) {
 
 void UART::write_mem_u8(uint8_t* src, size_t addr) {
   if (addr < UART_ADDR || addr + 1 > UART_ADDR + 8) {
-    throw std::runtime_error("Memory access out of bounds");
+    throw std::runtime_error(std::string("Memory access out of bounds: ") +
+                             std::format("{:x}", addr));
   }
   addr -= UART_ADDR;
   switch (addr) {
@@ -91,7 +93,8 @@ void VM::read_mem_u8(uint8_t* dst, size_t addr) {
       return;
     }
   }
-  throw std::runtime_error("Memory access out of bounds");
+  throw std::runtime_error(std::string("Memory access out of bounds: ") +
+                           std::format("{:x}", addr));
 }
 
 void VM::read_mem_u16(uint16_t* dst, size_t addr) {
@@ -101,7 +104,8 @@ void VM::read_mem_u16(uint16_t* dst, size_t addr) {
       return;
     }
   }
-  throw std::runtime_error("Memory access out of bounds");
+  throw std::runtime_error(std::string("Memory access out of bounds: ") +
+                           std::format("{:x}", addr));
 }
 
 void VM::read_mem_u32(uint32_t* dst, size_t addr) {
@@ -111,7 +115,8 @@ void VM::read_mem_u32(uint32_t* dst, size_t addr) {
       return;
     }
   }
-  throw std::runtime_error("Memory access out of bounds");
+  throw std::runtime_error(std::string("Memory access out of bounds: ") +
+                           std::format("{:x}", addr));
 }
 
 void VM::write_mem_u8(uint8_t* src, size_t addr) {
@@ -121,7 +126,8 @@ void VM::write_mem_u8(uint8_t* src, size_t addr) {
       return;
     }
   }
-  throw std::runtime_error("Memory access out of bounds");
+  throw std::runtime_error(std::string("Memory access out of bounds: ") +
+                           std::format("{:x}", addr));
 }
 
 void VM::write_mem_u16(uint16_t* src, size_t addr) {
@@ -131,7 +137,8 @@ void VM::write_mem_u16(uint16_t* src, size_t addr) {
       return;
     }
   }
-  throw std::runtime_error("Memory access out of bounds");
+  throw std::runtime_error(std::string("Memory access out of bounds: ") +
+                           std::format("{:x}", addr));
 }
 
 void VM::write_mem_u32(uint32_t* src, size_t addr) {
@@ -141,7 +148,8 @@ void VM::write_mem_u32(uint32_t* src, size_t addr) {
       return;
     }
   }
-  throw std::runtime_error("Memory access out of bounds");
+  throw std::runtime_error(std::string("Memory access out of bounds: ") +
+                           std::format("{:x}", addr));
 }
 
 std::vector<uint8_t> VM::read_memory(size_t start, size_t size) {