[clang] [AArch64] Implement FP8 floating-point mode helper intrinsics (PR #100608)

[via cfe-commits]

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@@ -2581,6 +2581,60 @@ void NeonEmitter::runVectorTypes(raw_ostream &OS) {
   OS << "typedef double float64_t;\n";
   OS << "#endif\n\n";
 
+  OS << R"(
+typedef uint64_t fpm_t;
+
+enum __ARM_FPM_FORMAT { __ARM_FPM_E5M2, __ARM_FPM_E4M3 };
+
+enum __ARM_FPM_OVERFLOW { __ARM_FPM_INFNAN, __ARM_FPM_SATURATE };
+
+static __inline__ fpm_t __attribute__((__always_inline__, __nodebug__))
+__arm_fpm_init(void) {
+  return 0;
+}
+
+static __inline__ fpm_t __attribute__((__always_inline__, __nodebug__))
+__arm_set_fpm_src1_format(fpm_t __fpm, enum __ARM_FPM_FORMAT __format) {
+  return (__fpm & ~7ull) | (fpm_t)__format;
+}
+
+static __inline__ fpm_t __attribute__((__always_inline__, __nodebug__))
+__arm_set_fpm_src2_format(fpm_t __fpm, enum __ARM_FPM_FORMAT __format) {
+  return (__fpm & ~0x38ull) | ((fpm_t)__format << 3u);
+}
+
+static __inline__ fpm_t __attribute__((__always_inline__, __nodebug__))
+__arm_set_fpm_dst_format(fpm_t __fpm, enum __ARM_FPM_FORMAT __format) {
+  return (__fpm & ~0x1c0ull) | ((fpm_t)__format << 6u);
+}
+
+static __inline__ fpm_t __attribute__((__always_inline__, __nodebug__))
+__arm_set_fpm_overflow_mul(fpm_t __fpm, enum __ARM_FPM_OVERFLOW __behaviour) {
+  return (__fpm & ~0x4000ull) | ((fpm_t)__behaviour << 14u);
+}
+
+static __inline__ fpm_t __attribute__((__always_inline__, __nodebug__))
+__arm_set_fpm_overflow_cvt(fpm_t __fpm, enum __ARM_FPM_OVERFLOW __behaviour) {
+  return (__fpm & ~0x8000ull) | ((fpm_t)__behaviour << 15u);
+}
+
+static __inline__ fpm_t __attribute__((__always_inline__, __nodebug__))
+__arm_set_fpm_lscale(fpm_t __fpm, uint64_t __scale) {
+  return (__fpm & ~0x7f0000ull) | (__scale << 16u);
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SpencerAbson wrote:

Does `__scale` not need to be masked by `0x7full` to prevent a user from writing past bit 22 here?

https://github.com/llvm/llvm-project/pull/100608