TZUTC: -0800   
   MSGID: 59111.sync_sys@1:103/705 2dbda0c2   
   PID: Synchronet 3.21a-Linux master/48922a15c Dec 17 2025 GCC 12.2.0   
   TID: SBBSecho 3.34-Linux master/8bb133aa7 Dec 30 2025 GCC 12.2.0   
   BBSID: VERT   
   CHRS: UTF-8 4   
   FORMAT: flowed   
   https://gitlab.synchro.net/main/sbbs/-/issues/685#note_8070   
      
   So, just took a look... while it's easy enough to extend the value to 48-bits   
   by taking a bit from the tag, it appears that newer version of SpiderMonkey do   
   *not* actually support more than 47 value bits   
      
   ie: `TAG_SHIFT` is still 47, and `bitsFromTagAndPayload()` is   
   ```C++   
     static constexpr uint64_t bitsFromTagAndPayload(JSValueTag tag,   
                                                     PayloadType payload) {   
       return (uint64_t(tag) << JSVAL_TAG_SHIFT) | payload;   
     }   
   ```   
      
   So I'm not sure how Firefox and GNOME are getting away with this, though the   
   `setarch` manpage perhaps has a hint:   
      
   ```   
      
          -L, --addr-compat-layout   
              Provide legacy virtual address space layout. Use when the   
              program binary does not have PT_GNU_STACK ELF header. Turns on   
              ADDR_COMPAT_LAYOUT.   
   ```   
      
   Is there some way to set `ADDR_COMPAT_LAYOUT` in the `PT_GNU_STACK` header via   
   linker flags?   
   --- SBBSecho 3.34-Linux   
    * Origin: Vertrauen - [vert/cvs/bbs].synchro.net (1:103/705)   
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