The application discloses a switchable precision floating-point multiplier-
adder, which comprises a four-stage pipeline, a first-stage pipeline, a second-stage pipeline, a third-stage pipeline and a fourth-stage pipeline; the first-stage pipeline comprises a distribution
processing module, a multiplier array module, an
adder array adding module and an exponent comparison module; the second-stage pipeline comprises an exponent difference module, an alignment shift module, an addition tree module and a compression module; the third-stage pipeline comprises a
leading zero prediction module, a
leading zero coding module, a sign prediction module and an advance calculation module; and the fourth-stage pipeline comprises a sum and rejection module and an exponent normalization module. The floating-point multiplier-
adder combines double-precision multiplication and addition to complete double-precision floating-point operation in the form of A+BxC, and the combination can greatly reuse the components in the multiplier-adder compared with a simple multiplier-adder combined with an adder. The application can be widely applied in the field of hardware operation devices.