80C186EB/80C188EB Microprocessor User's Manual - CEUNES

MATH COPROCESSING12.3.1.1 Data Transfer InstructionsData transfer instructions move operands between elements of the 80C187 register stack or betweenstack top and memory. Instructions can convert any data type to temporary real and load itonto the stack in a single operation. Conversely, instructions can convert a temporary real operandon the stack to any data type and store it to memory in a single operation. Table 12-1 summarizesthe data transfer instructions.Table 12-1. 80C187 Data Transfer InstructionsReal TransfersFLDFSTFSTPFXCHLoad realStore realStore real and popExchange registersInteger TransfersFILDFISTFISTPInteger loadInteger storeInteger store and popPacked Decimal TransfersFBLDFBSTPPacked decimal (BCD) loadPacked decimal (BCD) store and pop12.3.1.2 Arithmetic InstructionsThe 80C187’s arithmetic instruction set includes many variations of add, subtract, multiply, anddivide operations and several other useful functions. Examples include a simple absolute valueand a square root instruction that executes faster than ordinary division. Other arithmetic instructionsperform exact modulo division, round real numbers to integers and scale values by powersof two.Table 12-2 summarizes the available operation and operand forms for basic arithmetic. In additionto the four normal operations, “reversed” instructions make subtraction and division “symmetrical”like addition and multiplication. In summary, the arithmetic instructions are highlyflexible for these reasons:• the 80C187 uses register or memory operands• the 80C187 can save results in a choice of registers12-3