doc/register-usage.txt

   1 This is the Linux ABI register usage (also used by HVF):
   2
   3 r0       used by syscalls/assembly                  call-clobbered
   4 r1       used by syscalls/assembly                  call-clobbered
   5 r2       argument 0 / return value 0                call-clobbered
   6 r3       argument 1 / return value 1 (if long long) call-clobbered
   7 r4       argument 2                                 call-clobbered
   8 r5       argument 3                                 call-clobbered
   9 r6       argument 4                                 saved
  10 r7       pointer-to arguments 5 to ...              saved
  11 r8       this & that                                saved
  12 r9       this & that                                saved
  13 r10      static-chain ( if nested function )        saved
  14 r11      frame-pointer ( if function used alloca )  saved
  15 r12      got-pointer                                saved
  16 r13      base-pointer                               saved
  17 r14      return-address                             saved
  18 r15      stack-pointer                              saved