[PATCH v2] sh: libgcc: Implement fenv rouding and exceptions for soft-fp [PR118257]

[PATCH v2] sh: libgcc: Implement fenv rouding and exceptions for soft-fp [PR118257]

Implement fenv rouding and exceptions for soft-fp, as per SuperH
arch specification.

No new tests required, as it's already covered by many torture tests
with fenv_exceptions.

	PR target/118257

libgcc/ChangeLog:

	* config/sh/sfp-machine.h (_FPU_GETCW): Implement with builtin.
	(_FPU_SETCW): Likewise.
	(FP_EX_ENABLE_SHIFT): Derive from arch spec.
	(FP_EX_CAUSE_SHIFT): Likewise.
	(FP_RND_MASK): Likewise.
	(FP_EX_INVALID): Likewise.
	(FP_EX_DIVZERO): Likewise.
	(FP_EX_ALL): Likewise.
	(FP_EX_OVERFLOW): Likewise.
	(FP_EX_UNDERFLOW): Likewise.
	(FP_EX_INEXACT): Likewise.
	(_FP_DECL_EX): Declear default FCSR value.
	(FP_RND_NEAREST): Derive from arch spec.
	(FP_RND_ZERO): Likewise.
	(FP_INIT_ROUNDMODE): Likewise.
	(FP_ROUNDMODE): Likewise.
	(FP_TRAPPING_EXCEPTIONS): Likewise.
	(FP_HANDLE_EXCEPTIONS): Implement with _FPU_SETCW.