Understanding ARC-V configurations¶

GNU toolchain for ARC-V is shipped with a set of prebuilt libraries for each available configuration (so called multilib). A configuration is a combination of -march, -mabi, -mtune and -mcmodel values. The default value for -mtune (if it's not passed explicitly) is arc-v-rmx-100-series and the default value for -mcmodel is medlow.

Below you can find lists of all combinations of options for which prebuilt libraries are presented in the toolchain.

How multilib works¶

On linkage stage, when a set of target options is passed, GCC tries to select standard libraries that match this set of options. If you are not sure what prebuilt libraries are selected for linking with an application, you can use -print-multi-os-directory option to check this:

$ riscv64-snps-elf-gcc -march=rv32imafd_zca_zcmp -mabi=ilp32d -mtune=arc-v-rhx-100-series -print-multi-os-directory
rv32imafd_zca/ilp32d/rhx100

Output tells that the library compiled with -march=rv32imafd_zca -mabi=ilp32d -mtune=arc-v-rhx-100-series is chosen for linking. -march=rv32imafd_zca_zcmp is a superset of -march=rv32imafd_zca and the most compatible variant is chosen.

Consider another example:

$ riscv64-snps-elf-gcc -march=rv32imafd -mabi=ilp32d -mtune=arc-v-rhx-100-series -print-multi-os-directory
.

There is no prebuilt libraries for this set of options since the nearest compatible -march value for this combination is rv32imafd_zca. Thus, output is just "." . That means, that the default library is chosen.

You can find a full list of all multilib configurations this way:

$ riscv64-snps-elf-gcc -print-multi-lib
.;
rv32e/ilp32e;@march=rv32e@mabi=ilp32e
rv32em/ilp32e;@march=rv32em@mabi=ilp32e
rv32ea/ilp32e;@march=rv32ea@mabi=ilp32e
rv32ema/ilp32e;@march=rv32ema@mabi=ilp32e
rv32emac_zcb_zba_zbb_zbs_zfinx_zdinx/ilp32e;@march=rv32emac_zcb_zba_zbb_zbs_zfinx_zdinx@mabi=ilp32e
rv32i/ilp32;@march=rv32i@mabi=ilp32
rv32i/ilp32/rmx500;@march=rv32i@mabi=ilp32@mtune=arc-v-rmx-500-series
rv32i/ilp32/rhx100;@march=rv32i@mabi=ilp32@mtune=arc-v-rhx-100-series
rv32ic/ilp32;@march=rv32ic@mabi=ilp32
rv32ic/ilp32/rmx500;@march=rv32ic@mabi=ilp32@mtune=arc-v-rmx-500-series
rv32ic/ilp32/rhx100;@march=rv32ic@mabi=ilp32@mtune=arc-v-rhx-100-series
rv32im/ilp32;@march=rv32im@mabi=ilp32
...

Configurations for RMX-100 mini targets¶

ARC-V profile	`-march`	`-mabi`	`-mtune`	`-mcmodel`
Base RMX-100 mini	`rv32e`	`ilp32e`	`arc-v-rmx-100-series`	`medlow`
Base RMX-100 mini + `M`	`rv32em`	`ilp32e`	`arc-v-rmx-100-series`	`medlow`
Base RMX-100 mini + `A`	`rv32ea`	`ilp32e`	`arc-v-rmx-100-series`	`medlow`
Base RMX-100 mini + `MA`	`rv32ema`	`ilp32e`	`arc-v-rmx-100-series`	`medlow`
Full-featured RMX-100 mini	`rv32emac_zcb_zba_zbb_zbs_zfinx_zdinx`	`ilp32e`	`arc-v-rmx-100-series`	`medlow`

Configurations for RMX-100 targets¶

ARC-V profile	`-march`	`-mabi`	`-mtune`	`-mcmodel`
Generic RISC-V	`rv32i`	`ilp32`	`arc-v-rmx-100-series`	`medlow`
Generic RISC-V	`rv32ic`	`ilp32`	`arc-v-rmx-100-series`	`medlow`
Generic RISC-V	`rv32im`	`ilp32`	`arc-v-rmx-100-series`	`medlow`
Generic RISC-V	`rv32imc`	`ilp32`	`arc-v-rmx-100-series`	`medlow`
Generic RISC-V	`rv32ia`	`ilp32`	`arc-v-rmx-100-series`	`medlow`
Generic RISC-V	`rv32ima`	`ilp32`	`arc-v-rmx-100-series`	`medlow`
Generic RISC-V	`rv32iac`	`ilp32`	`arc-v-rmx-100-series`	`medlow`
Generic RISC-V	`rv32imac`	`ilp32`	`arc-v-rmx-100-series`	`medlow`
Base RMX-100	`rv32ic_zcb_zba_zbb_zbs`	`ilp32`	`arc-v-rmx-100-series`	`medlow`
Base RMX-100 + `M`	`rv32imc_zcb_zba_zbb_zbs`	`ilp32`	`arc-v-rmx-100-series`	`medlow`
Base RMX-100 + `MA`	`rv32imac_zcb_zba_zbb_zbs`	`ilp32`	`arc-v-rmx-100-series`	`medlow`
Base RMX-100 + `MA`, `Zfinx`	`rv32imac_zcb_zba_zbb_zbs_zfinx`	`ilp32`	`arc-v-rmx-100-series`	`medlow`
Base RMX-100 + `MA`, `Zfinx`, `Zdinx`	`rv32imac_zcb_zba_zbb_zbs_zfinx_zdinx`	`ilp32`	`arc-v-rmx-100-series`	`medlow`
Base RMX-100 without `C`	`rv32i_zba_zbb_zbs`	`ilp32`	`arc-v-rmx-100-series`	`medlow`
Base RMX-100 + `M` without `C`	`rv32im_zba_zbb_zbs`	`ilp32`	`arc-v-rmx-100-series`	`medlow`
Base RMX-100 + `MA` without `C`	`rv32ima_zba_zbb_zbs`	`ilp32`	`arc-v-rmx-100-series`	`medlow`
Base RMX-100 + `MA`, `Zfinx` without `C`	`rv32ima_zba_zbb_zbs_zfinx`	`ilp32`	`arc-v-rmx-100-series`	`medlow`
Base RMX-100 + `MA`, `Zfinx`, `Zdinx` without `C`	`rv32ima_zba_zbb_zbs_zfinx_zdinx`	`ilp32`	`arc-v-rmx-100-series`	`medlow`

Configurations for RMX-500 targets¶

ARC-V profile	`-march`	`-mabi`	`-mtune`	`-mcmodel`
Generic RISC-V	`rv32i`	`ilp32`	`arc-v-rmx-100-series`	`medlow`
Generic RISC-V	`rv32ic`	`ilp32`	`arc-v-rmx-100-series`	`medlow`
Generic RISC-V	`rv32im`	`ilp32`	`arc-v-rmx-100-series`	`medlow`
Generic RISC-V	`rv32imc`	`ilp32`	`arc-v-rmx-100-series`	`medlow`
Generic RISC-V	`rv32ia`	`ilp32`	`arc-v-rmx-100-series`	`medlow`
Generic RISC-V	`rv32ima`	`ilp32`	`arc-v-rmx-100-series`	`medlow`
Generic RISC-V	`rv32iac`	`ilp32`	`arc-v-rmx-100-series`	`medlow`
Generic RISC-V	`rv32imac`	`ilp32`	`arc-v-rmx-100-series`	`medlow`
Base RMX-500	`rv32ic_zcb_zba_zbb_zbs`	`ilp32`	`arc-v-rmx-100-series`	`medlow`
Base RMX-500 + `M`	`rv32imc_zcb_zba_zbb_zbs`	`ilp32`	`arc-v-rmx-100-series`	`medlow`
Base RMX-500 + `MA`	`rv32imac_zcb_zba_zbb_zbs`	`ilp32`	`arc-v-rmx-100-series`	`medlow`
Base RMX-500 + `MA`, `Zfinx`	`rv32imac_zcb_zba_zbb_zbs_zfinx`	`ilp32`	`arc-v-rmx-100-series`	`medlow`
Base RMX-500 + `MA`, `Zfinx`, `Zdinx`	`rv32imac_zcb_zba_zbb_zbs_zfinx_zdinx`	`ilp32`	`arc-v-rmx-100-series`	`medlow`

Configurations for RHX-100 targets¶

ARC-V profile	`-march`	`-mabi`	`-mtune`	`-mcmodel`
Generic RISC-V	`rv32i`	`ilp32`	`arc-v-rhx-100-series`	`medlow`
Generic RISC-V	`rv32ic`	`ilp32`	`arc-v-rhx-100-series`	`medlow`
Generic RISC-V	`rv32im`	`ilp32`	`arc-v-rhx-100-series`	`medlow`
Generic RISC-V	`rv32imc`	`ilp32`	`arc-v-rhx-100-series`	`medlow`
Generic RISC-V	`rv32ia`	`ilp32`	`arc-v-rhx-100-series`	`medlow`
Generic RISC-V	`rv32ima`	`ilp32`	`arc-v-rhx-100-series`	`medlow`
Generic RISC-V	`rv32iac`	`ilp32`	`arc-v-rhx-100-series`	`medlow`
Generic RISC-V	`rv32imac`	`ilp32`	`arc-v-rhx-100-series`	`medlow`
Generic RISC-V	`rv32imafc`	`ilp32f`	`arc-v-rhx-100-series`	`medlow`
Generic RISC-V	`rv32imafd_zca`¹	`ilp32d`	`arc-v-rhx-100-series`	`medlow`
Base RHX-100	`rv32imac_zcb_zba_zbb_zbs`	`ilp32`	`arc-v-rhx-100-series`	`medlow`
Base RHX-100 + `F`	`rv32imafc_zcb_zba_zbb_zbs`	`ilp32f`	`arc-v-rhx-100-series`	`medlow`
Base RHX-100 + `FD`	`rv32imafd_zca_zcb_zba_zbb_zbs`¹	`ilp32d`	`arc-v-rhx-100-series`	`medlow`

Configurations for RPX-100 targets¶

ARC-V profile	`-march`	`-mabi`	`-mtune`	`-mcmodel`
Generic RISC-V	`rv64i`	`lp64`	`arc-v-rpx-100-series`	`medany`²
Generic RISC-V	`rv64ic`	`lp64`	`arc-v-rpx-100-series`	`medany`
Generic RISC-V	`rv64im`	`lp64`	`arc-v-rpx-100-series`	`medany`
Generic RISC-V	`rv64imc`	`lp64`	`arc-v-rpx-100-series`	`medany`
Generic RISC-V	`rv64ia`	`lp64`	`arc-v-rpx-100-series`	`medany`
Generic RISC-V	`rv64ima`	`lp64`	`arc-v-rpx-100-series`	`medany`
Generic RISC-V	`rv64iac`	`lp64`	`arc-v-rpx-100-series`	`medany`
Generic RISC-V	`rv64imac`	`lp64`	`arc-v-rpx-100-series`	`medany`
Generic RISC-V	`rv64imafdc`	`lp64d`	`arc-v-rpx-100-series`	`medany`
Base RPX-100	`rv64imac_zcb_zba_zbb_zbs`¹	`lp64`	`arc-v-rpx-100-series`	`medany`
Base RPX-100	`rv64imafdc_zcb_zba_zbb_zbs`	`lp64d`	`arc-v-rpx-100-series`	`medany`

Note that this configuration does not include zcd in -march since it's not supported by RHX-100. ↩↩↩
In the GNU toolchain 64-bit targets are available only for -mcmodel=medany memory model. ↩