PDP-11 Options - Using the GNU Compiler Collection (GCC)

These options are defined for the PDP-11:

-mfpu: Use hardware FPP floating point. This is the default. (FIS floating point on the PDP-11/40 is not supported.)
-msoft-float: Do not use hardware floating point.
-mac0: Return floating-point results in ac0 (fr0 in Unix assembler syntax).
-mno-ac0: Return floating-point results in memory. This is the default.
-m40: Generate code for a PDP-11/40.
-m45: Generate code for a PDP-11/45. This is the default.
-m10: Generate code for a PDP-11/10.
-mbcopy-builtin: Use inline movmemhi patterns for copying memory. This is the default.
-mbcopy: Do not use inline movmemhi patterns for copying memory.
-mint16
-mno-int32: Use 16-bit int. This is the default.
-mint32
-mno-int16: Use 32-bit int.
-mfloat64
-mno-float32: Use 64-bit float. This is the default.
-mfloat32
-mno-float64: Use 32-bit float.
-mabshi: Use abshi2 pattern. This is the default.
-mno-abshi: Do not use abshi2 pattern.
-mbranch-expensive: Pretend that branches are expensive. This is for experimenting with code generation only.
-mbranch-cheap: Do not pretend that branches are expensive. This is the default.
-munix-asm: Use Unix assembler syntax. This is the default when configured for ‘pdp11-*-bsd’.
-mdec-asm: Use DEC assembler syntax. This is the default when configured for any PDP-11 target other than ‘pdp11-*-bsd’.