Abstract: A system, structure and method using radix-1000 (instead of radix-10) are implemented to represent and operate on decimal floating-point numbers. Instead of using a 10-bit declet to encode a DPD, the system, structure and method herein use a declet to encode a BCK (Binary Coded 1000 values), where the letter K is the abbreviation of the number 1000. A skewed representation of the fraction field is then used to avoid the loss of decimal digits in arithmetic operations when shifting and rounding the fraction are required.

Abstract: The structured control instruction fetch unit is a structured instruction stream controller that processes expand (XP), expand register indirect (XPR), loop (LOOP), and break (BRK) instructions for structured control. The fetch unit processes stop bits that mark the end of instruction blocks. Any instruction can be marked with a stop bit to indicate that it is the last one in an instruction block. All instructions are encoded with a predicate to reduce the use of control instructions and to simplify the control. A control stack guides instruction fetching by storing return addresses, loop block addresses, loop predicates, and loop counters. Control instructions and stop bits manage operation of the control stack. An instruction unit feeds execution units and includes a set-associative instruction cache, a control stack, an instruction buffer that decouples instruction fetching from execution, instruction decoders, and program counter (PC) control logic.

Abstract: A microprocessor including an instruction set architecture includes: a decode and fetch control; a instruction cache; a data cache; a control stack; and an instruction set including a stop bit; a qualifying predicate; an opcode, a register and/or an immediate operand.

Abstract: The structured control instruction fetch unit is a structured instruction stream controller that processes expand (XP), expand register indirect (XPR), loop (LOOP), and break (BRK) instructions for structured control. The fetch unit processes stop bits that mark the end of instruction blocks. Any instruction can be marked with a stop bit to indicate that it is the last one in an instruction block. All instructions are encoded with a predicate to reduce the use of control instructions and to simplify the control. A control stack guides instruction fetching by storing return addresses, loop block addresses, loop predicates, and loop counters. Control instructions and stop bits manage operation of the control stack. An instruction unit feeds execution units and includes a set-associative instruction cache, a control stack, an instruction buffer that decouples instruction fetching from execution, instruction decoders, and program counter (PC) control logic.