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Diffstat (limited to 'usr/klibc/arch/alpha/README-gcc')
| -rw-r--r-- | usr/klibc/arch/alpha/README-gcc | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/usr/klibc/arch/alpha/README-gcc b/usr/klibc/arch/alpha/README-gcc new file mode 100644 index 0000000..1d0052f --- /dev/null +++ b/usr/klibc/arch/alpha/README-gcc @@ -0,0 +1,22 @@ + The current Alpha chips don't provide hardware for integer + division. The C compiler expects the functions + + __divqu: 64-bit unsigned long divide + __remqu: 64-bit unsigned long remainder + __divq/__remq: signed 64-bit + __divlu/__remlu: unsigned 32-bit + __divl/__reml: signed 32-bit + + These are not normal C functions: instead of the normal calling + sequence, these expect their arguments in registers t10 and t11, and + return the result in t12 (aka pv). Register AT may be clobbered + (assembly temporary), anything else must be saved. + + Furthermore, the return address is in t9 instead of ra. + + Normal function Divide functions + --------------- ---------------- + v0 ($0) t12/pv ($27) + a0 ($16) t10 ($24) + a1 ($17) t11 ($25) + ra ($26) t9 ($23) |