src/librustc_target/spec/thumbv7em_none_eabihf.rs

   1 // Targets the Cortex-M4F and Cortex-M7F processors (ARMv7E-M)
   2 //
   3 // This target assumes that the device does have a FPU (Floating Point Unit) and lowers all (single
   4 // precision) floating point operations to hardware instructions.
   5 //
   6 // Additionally, this target uses the "hard" floating convention (ABI) where floating point values
   7 // are passed to/from subroutines via FPU registers (S0, S1, D0, D1, etc.).
   8 //
   9 // To opt into double precision hardware support, use the `-C target-feature=+fp64` flag.
  10
  11 use crate::spec::{LinkerFlavor, LldFlavor, Target, TargetOptions, TargetResult};
  12
  13 pub fn target() -> TargetResult {
  14     Ok(Target {
  15         llvm_target: "thumbv7em-none-eabihf".to_string(),
  16         target_endian: "little".to_string(),
  17         target_pointer_width: "32".to_string(),
  18         target_c_int_width: "32".to_string(),
  19         data_layout: "e-m:e-p:32:32-Fi8-i64:64-v128:64:128-a:0:32-n32-S64".to_string(),
  20         arch: "arm".to_string(),
  21         target_os: "none".to_string(),
  22         target_env: String::new(),
  23         target_vendor: String::new(),
  24         linker_flavor: LinkerFlavor::Lld(LldFlavor::Ld),
  25
  26         options: TargetOptions {
  27             // `+vfp4` is the lowest common denominator between the Cortex-M4 (vfp4-16) and the
  28             // Cortex-M7 (vfp5)
  29             // `-d32` both the Cortex-M4 and the Cortex-M7 only have 16 double-precision registers
  30             // available
  31             // `-fp64` The Cortex-M4 only supports single precision floating point operations
  32             // whereas in the Cortex-M7 double precision is optional
  33             //
  34             // Reference:
  35             // ARMv7-M Architecture Reference Manual - A2.5 The optional floating-point extension
  36             features: "+vfp4,-d32,-fp64".to_string(),
  37             max_atomic_width: Some(32),
  38             ..super::thumb_base::opts()
  39         },
  40     })
  41 }