5188

Clean up some unused constants.

2 files changed, 9 insertions, 12 deletions

diff --git a/subx/012elf.cc b/subx/012elf.cc
index 0ae0b108..da70adec 100644
--- a/subx/012elf.cc
+++ b/subx/012elf.cc
@@ -138,15 +138,13 @@ void load_segment_from_program_header(uint8_t* elf_contents, int segment_index,
 
 :(before "End Includes")
 // Very primitive/fixed/insecure ELF segments for now.
-//   code:  0x09000000 -> 0x09ffffff (specified in ELF binary)
-//   data:  0x0a000000 -> 0x0affffff (specified in ELF binary)
-//   --- heap gets mmap'd somewhere here ---
-//   stack: 0xbdffffff -> 0xbd000000 (downward; not in ELF binary)
-//   argv hack: 0xbf000000 -> 0xbfffffff (not in ELF binary)
-//
-// Addresses above 0xc0000000 are reserved for the Linux kernel.
-const uint32_t CODE_SEGMENT      = 0x09000000;
-const uint32_t DATA_SEGMENT      = 0x0a000000;
+//   --- inaccessible:        0x00000000 -> 0x08047fff
+//   code:                    0x09000000 -> 0x09ffffff (specified in ELF binary)
+//   data:                    0x0a000000 -> 0x0affffff (specified in ELF binary)
+//                      --- heap gets mmap'd somewhere here ---
+//   stack:                   0xbdffffff -> 0xbd000000 (downward; not in ELF binary)
+//   argv hack:               0xbf000000 -> 0xbfffffff (not in ELF binary)
+//   --- reserved for kernel: 0xc0000000 -> ...
 const uint32_t START_HEAP        = 0x0b000000;
 const uint32_t END_HEAP          = 0xbd000000;
 const uint32_t STACK_SEGMENT     = 0xbd000000;
diff --git a/subx/020syscalls.cc b/subx/020syscalls.cc
index eb8ebcce..eb72f85d 100644
--- a/subx/020syscalls.cc
+++ b/subx/020syscalls.cc
@@ -112,15 +112,14 @@ void check_mode(int reg) {
 :(before "End Globals")
 // Very primitive/fixed/insecure mmap segments for now.
 uint32_t Segments_allocated_above = END_HEAP;
-const uint32_t SPACE_FOR_SEGMENT = 0x01000000;
 :(code)
 // always allocate multiples of the segment size
 uint32_t new_segment(uint32_t length) {
   assert(length > 0);
-  uint32_t result = (Segments_allocated_above - length) & 0xff000000;
+  uint32_t result = (Segments_allocated_above - length) & 0xff000000;  // same number of zeroes as SEGMENT_ALIGNMENT
   if (result <= START_HEAP) {
     raise << "Allocated too many segments; the VM ran out of memory. "
-          << "Maybe SPACE_FOR_SEGMENT can be smaller?\n" << end();
+          << "Maybe SEGMENT_ALIGNMENT can be smaller?\n" << end();
     exit(1);
   }
   Mem.push_back(vma(result, result+length));