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

#### 3.20.37 PDP-11 Options ¶

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.) Implies `-m45`.

`-msoft-float` ¶

  Do not use hardware floating point.

`-mac0` ¶
`-mno-ac0`

  With `-mac0`, return floating-point results in ac0 (fr0 in Unix assembler syntax). The default, `-mno-ac0`, is to return floating-point results in memory.

`-m40` ¶

  Generate code for a PDP-11/40. Implies `-msoft-float` `-mno-split`.

`-m45` ¶

  Generate code for a PDP-11/45. This is the default.

`-m10` ¶

  Generate code for a PDP-11/10. Implies `-msoft-float` `-mno-split`.

`-mint16` ¶
`-mno-int32`

  Use 16-bit `int`. This is the default.

`-mint32` ¶
`-mno-int16`

  Use 32-bit `int`.

`-msplit` ¶

  Target has split instruction and data space. Implies `-m45`.

`-munix-asm` ¶

  Use Unix assembler syntax.

`-mdec-asm` ¶

  Use DEC assembler syntax.

`-mgnu-asm` ¶

  Use GNU assembler syntax. This is the default.

`-mlra` ¶

  Use the new LRA register allocator. By default, the old “reload” allocator is used.