diff options
Diffstat (limited to 'subx/010vm.cc')
| -rw-r--r-- | subx/010vm.cc | 12 |
1 files changed, 7 insertions, 5 deletions
diff --git a/subx/010vm.cc b/subx/010vm.cc index 67c407a8..9d6d047d 100644 --- a/subx/010vm.cc +++ b/subx/010vm.cc @@ -31,12 +31,14 @@ EIP = 1; // preserve null pointer cerr << " registers\n"; :(before "End Help Texts") put(Help, "registers", - "SubX currently supports 8 integer registers, numbered from 0 to 7.\n" + "SubX currently supports eight 32-bit integer registers: R0 to R7.\n" + "R4 contains the top of the stack.\n" "There's also a register for the address of the currently executing instruction. It is modified by jumps.\n" - "Various instructions modify one or more of 3 flags, as a side-effect:\n" - "- the sign flag: usually set if an arithmetic result is negative, or reset if not.\n" - "- the zero flag: usually set if a result is zero, or reset if not.\n" - "- the overflow flag: usually set if an arithmetic result overflows.\n" + "Various instructions modify one or more of three 1-bit 'flag' registers, as a side-effect:\n" + "- the sign flag (SF): usually set if an arithmetic result is negative, or reset if not.\n" + "- the zero flag (ZF): usually set if a result is zero, or reset if not.\n" + "- the overflow flag (OF): usually set if an arithmetic result overflows.\n" + "The flag bits are read by conditional jumps.\n" "We don't support non-integer (floating-point) registers yet.\n" ); |