Next: PDP-11-Pseudos, Up: PDP-11-Dependent

#### 9.27.1 Options

The PDP-11 version of `as` has a rich set of machine dependent options.

##### 9.27.1.1 Code Generation Options

`-mpic | -mno-pic`
  Generate position-independent (or position-dependent) code.

  The default is to generate position-independent code.

##### 9.27.1.2 Instruction Set Extension Options

These options enables or disables the use of extensions over the base line instruction set as introduced by the first PDP-11 CPU: the KA11. Most options come in two variants: a `-m` extension that enables extension, and a `-mno-`extension that disables extension.

The default is to enable all extensions.

`-mall | -mall-extensions`
  Enable all instruction set extensions.

`-mno-extensions`
  Disable all instruction set extensions.

`-mcis | -mno-cis`
  Enable (or disable) the use of the commercial instruction set, which consists of these instructions: `ADDNI`, `ADDN`, `ADDPI`, `ADDP`, `ASHNI`, `ASHN`, `ASHPI`, `ASHP`, `CMPCI`, `CMPC`, `CMPNI`, `CMPN`, `CMPPI`, `CMPP`, `CVTLNI`, `CVTLN`, `CVTLPI`, `CVTLP`, `CVTNLI`, `CVTNL`, `CVTNPI`, `CVTNP`, `CVTPLI`, `CVTPL`, `CVTPNI`, `CVTPN`, `DIVPI`, `DIVP`, `L2DR`, `L3DR`, `LOCCI`, `LOCC`, `MATCI`, `MATC`, `MOVCI`, `MOVC`, `MOVRCI`, `MOVRC`, `MOVTCI`, `MOVTC`, `MULPI`, `MULP`, `SCANCI`, `SCANC`, `SKPCI`, `SKPC`, `SPANCI`, `SPANC`, `SUBNI`, `SUBN`, `SUBPI`, and `SUBP`.

`-mcsm | -mno-csm`
  Enable (or disable) the use of the `CSM` instruction.

`-meis | -mno-eis`
  Enable (or disable) the use of the extended instruction set, which consists of these instructions: `ASHC`, `ASH`, `DIV`, `MARK`, `MUL`, `RTT`, `SOB` `SXT`, and `XOR`.

`-mfis | -mkev11`
`-mno-fis | -mno-kev11`
  Enable (or disable) the use of the KEV11 floating-point instructions: `FADD`, `FDIV`, `FMUL`, and `FSUB`.

`-mfpp | -mfpu | -mfp-11`
`-mno-fpp | -mno-fpu | -mno-fp-11`
  Enable (or disable) the use of FP-11 floating-point instructions: `ABSF`, `ADDF`, `CFCC`, `CLRF`, `CMPF`, `DIVF`, `LDCFF`, `LDCIF`, `LDEXP`, `LDF`, `LDFPS`, `MODF`, `MULF`, `NEGF`, `SETD`, `SETF`, `SETI`, `SETL`, `STCFF`, `STCFI`, `STEXP`, `STF`, `STFPS`, `STST`, `SUBF`, and `TSTF`.

`-mlimited-eis | -mno-limited-eis`
  Enable (or disable) the use of the limited extended instruction set: `MARK`, `RTT`, `SOB`, `SXT`, and `XOR`.

  The -mno-limited-eis options also implies -mno-eis.

`-mmfpt | -mno-mfpt`
  Enable (or disable) the use of the `MFPT` instruction.

`-mmultiproc | -mno-multiproc`
  Enable (or disable) the use of multiprocessor instructions: `TSTSET` and `WRTLCK`.

`-mmxps | -mno-mxps`
  Enable (or disable) the use of the `MFPS` and `MTPS` instructions.

`-mspl | -mno-spl`
  Enable (or disable) the use of the `SPL` instruction.

  Enable (or disable) the use of the microcode instructions: `LDUB`, `MED`, and `XFC`.

##### 9.27.1.3 CPU Model Options

These options enable the instruction set extensions supported by a particular CPU, and disables all other extensions.

`-mka11`
  KA11 CPU. Base line instruction set only.

`-mkb11`
  KB11 CPU. Enable extended instruction set and `SPL`.

`-mkd11a`
  KD11-A CPU. Enable limited extended instruction set.

`-mkd11b`
  KD11-B CPU. Base line instruction set only.

`-mkd11d`
  KD11-D CPU. Base line instruction set only.

`-mkd11e`
  KD11-E CPU. Enable extended instruction set, `MFPS`, and `MTPS`.

`-mkd11f | -mkd11h | -mkd11q`
  KD11-F, KD11-H, or KD11-Q CPU. Enable limited extended instruction set, `MFPS`, and `MTPS`.

`-mkd11k`
  KD11-K CPU. Enable extended instruction set, `LDUB`, `MED`, `MFPS`, `MFPT`, `MTPS`, and `XFC`.

`-mkd11z`
  KD11-Z CPU. Enable extended instruction set, `CSM`, `MFPS`, `MFPT`, `MTPS`, and `SPL`.

`-mf11`
  F11 CPU. Enable extended instruction set, `MFPS`, `MFPT`, and `MTPS`.

`-mj11`
  J11 CPU. Enable extended instruction set, `CSM`, `MFPS`, `MFPT`, `MTPS`, `SPL`, `TSTSET`, and `WRTLCK`.

`-mt11`
  T11 CPU. Enable limited extended instruction set, `MFPS`, and `MTPS`.

##### 9.27.1.4 Machine Model Options

These options enable the instruction set extensions supported by a particular machine model, and disables all other extensions.

`-m11/03`
  Same as `-mkd11f`.

`-m11/04`
  Same as `-mkd11d`.

`-m11/05 | -m11/10`
  Same as `-mkd11b`.

`-m11/15 | -m11/20`
  Same as `-mka11`.

`-m11/21`
  Same as `-mt11`.

`-m11/23 | -m11/24`
  Same as `-mf11`.

`-m11/34`
  Same as `-mkd11e`.

`-m11/34a`
  Ame as `-mkd11e` `-mfpp`.

`-m11/35 | -m11/40`
  Same as `-mkd11a`.

`-m11/44`
  Same as `-mkd11z`.

`-m11/45 | -m11/50 | -m11/55 | -m11/70`
  Same as `-mkb11`.

`-m11/53 | -m11/73 | -m11/83 | -m11/84 | -m11/93 | -m11/94`
  Same as `-mj11`.

`-m11/60`
  Same as `-mkd11k`.