ry byte boundary. A longword is a 32-bit value. A longword is supported in the Alpha architecture by sign-extended load and store instructions and by longword arithmetic instructions.QuadwordA quadword is 8 contiguous bytes that start at an arbitrary byte boundary. A quadword is supported in Alpha architecture by load and store instructions and quadword integer operate instructions.(7, pg. 1-2)Numbers are also represented using floating-point notation. Floating point notation is just that, the radix, or decimal point is allowed to “float” or move left or right as needed. This allows the values to become either very precise or very large. The Alpha 21164 supports IEEE 754 & 854, and VAX floating point formats. IEEE (Institute of Electrical and Electronics Engineers) addressed the lack of transportability of floating point data among different computers by setting standards for both 32- and 64-bit floating point coding formats.The Alpha 21164 provides support for both S_floating formats and T_floating. S_floating (single precision), datum occupies four contiguous bytes in memory or 32 bits numbered 31 through 0. The 31st bit is the signed bit (indicates negative or positive values), bits 30 through 23 represent exponents, and bits 22 through 0 represent the fraction. The store instruction reorders register bits on the way to memory and does no checking of the low-order fraction bits. Thus register bits 61 through 59 and 28 through 0 are ignored. The load instruction reorders bits on the way in from memory. In doing so, the exponent is expanded from 8 to 11 bits, and the low-order fraction bits are set to zero. This produces an equivalent T_floating number.An IEEE double precision, or T_floating, datum occupies eight contiguous bytes in memory. The bits are labeled from right to left, 0 through 63.Bit 63 is a signed bit, bits 62 through 52 repre-sent the exponent, and bits 51 through 0 represent a 52-bit fraction. In IEEE T_flo...
