Data processor having an addressable local memory linked to a memory stack as an extension thereof

Claim 2

In a programmable data processing system, the combination comprising an arithmetic unit; a main memory having a first access time for storing stacks of information; a stack mechanism for reading and writing information in stacks; an addressable stack extension memory linked to a stack of information in the main memory for capturing information items that can be referred to in a programmatic procedure building the stack, the stack extension memory having a second lower access time so that it can be accessed more quickly than the main memory; and means responsive to a predetermined program operator for selecting an address of the stack extension memory for access and for coupling an information item captured therein to the arithmetic unit.

Claim 3

In a data processing system according to claim 1 wherein said coupling means comprises a pair of registers, in addition to said main memory and stack extension memory, into which information items are stored for processing by said arithmetic unit.

Claim 4

In a data processing system according to claim 1 wherein said stack mechanism is operable for writing information into and subsequently reading information out of said stack extension memory on a first in last out sequence for processing by said arithmetic unit.

Claim 5

In a data processing system according to claim 3 comprising means for indicating when said stack extension memory is full, said stack mechanism having means responsive to a full indication for writing in and reading out additional information items into a stack in said main memory which stack extends out from the top of the stack of information items in said stack extension memory.

Claim 6

In a data processing system according to claim 1 comprising means for addressing memory location in said stack extension memory and for reading out an information item therefrom for coupling to said arithmetic unit.

Claim 7

A data processing system comprising a main memory for storing stacks of information, a stack mechanism for reading or writing information in stacks in the memory and a register coupled to an arithmetic unit and to the main memory for exchanging information therebetween, a plurality of addressable registers for capturing information items that can be referred to in a programmatic procedure building a stack; first means for linking the addressable registers to a stack in memory so that they form a stack extension, the first means including means responsive to predetermined program operators for exchanging information items between the register coupled to the arithmetic unit and the addressable registers on a last in, first out basis; and second means responsive to other predetermined program operators for selecting any one of the addressable registers and coupling information items captured therein to the register coupled to the arithmetic unit.

Claim 8

A data processing system comprising a main memory for storing stacks of information, a stack mechanism for reading or writing information in stacks in the memory and a register coupled to an arithmetic unit and to the main memory for exchanging information therebetween, a plurality of addressable registers for capturing information items that can be referred to in a programmatic procedure building a stack; first means for linking the addressable registers to a stack in memory so that they form a stack extension, the first means including means responsive to predetermined program operators for exchanging information items between the register coupled to the arithmetic unit and the addressable registers on a last in, first out basis; and second means responsive to other predetermined program operators for selecting any one of the addressable registers and coupling information items captured therein to the register coupled to the arithmetic unit.

Claim 9

The system as defined in claim 6 wherein the first means includes stack extension pointing means for storing an indication of the addressable register containing the information item which was last written in and which has not yet been read out of the stack extension registers by the first means, thereby pointing to the top information item in the stack extension.

Claim 10

The apparatus as defined in claim 7 wherein the stack extension pointing means comprises a plurality of flip flop circuits connected in tandem to form a shift register, means for coupling the stack extension registers to the flip flops so that a one to one correspondence exists between the registers and the flip flops, and means for shifting an indicating signal up and down within the shift register so that the indicating signal is stored by the flip flop corresponding to the register containing the information item at the top of the stack extension.

Claim 11

The apparatus as defined in claim 8 wherein the shift register further includes a flip flop for storing an indicating signal when the stack extension is empty.

Claim 12

The apparatus as defined in claim 6 wherein the first means includes a register for storing an indication of a main memory location reserved for storing an information item in main memory from which the information items in the stack extension registers extend, thereby serving to link the information time in the stack extension register to the rest of a stack of information in the main memory.

Claim 13

The apparatus as defined in claim 10 wherein the means for exchanging information items with the addressable stack extension registers on a last in, first out basis is further operative to adjust the register for storing an indication of a main memory location so that it points to incrementally different memory locations.

Claim 14

A data processing system comprising main memory means for storing program operators of procedures and words for processing; a processor including a local memory having a plurality of addressable registers and having means for indicating that it is full when all its addressable registers contain words and when it is not full; and a stack mechanism responsive to a string of program operators and an indication that the local memory is not full for storing words obtained from the main memory into sequential locations of the local memory thereby building a stack in the local memory and responsive to the string of program operators and an indication that the local memory is full for storing additional words into sequential locations of the main memory thereby building in the main memory a stack which represents an overflow of the stack in the local memory, the stack mechanism including a register adjustable for storing while the stack is being built in the local memory an indication of a main memory location reserved for storing the current word at the top of the stack in the local memory thereby establishing a one to one correspondence between local and main memory locations and adjustable for storing while the overflow stack is being built in the main memory an indication of the main memory location actually storing the word at the top of the stack in main memory, the stack mechanism having means responsive to a predetermined program operator for inserting a mark word into the stack to mark a stack area to be used to store words for a procedure and having means responsive to another predetermined program operator directing the processor to enter a called from a calling procedure to transfer from the registers of the local memory to the corresponding locations of the main memory the part of the stack that was built up in the local memory by the calling procedure, thereby making those registers available for use in executing the called procedure.

Claim 15

A data processing system comprising main memory means for storing program operators of procedures and words for processing; a processor including a local memory having a plurality of addressable registers and having means for indicating that it is full when all its addressable registers contain words and when it is not full; and a stack mechanism responsive to a string of program operators and an indication that the local memory is not full for storing words obtained from the main memory into sequential locations of the local memory thereby building a stack in the local memory and responsive to the string of program operators and an indication that the local memory is full for storing additional words into sequential locations of the main memory thereby building in the main memory a stack which represents an overflow of the stack in the local memory, the stack mechanism including a register adjustable for storing while the stack is being built in the local memory an indication of a main memory location reserved for storing the current word at the top of the stack in the local memory thereby establishing a one to one correspondence between local and main memory locations and adjustable for storing while the overflow stack is being built in the main memory an indication of the main memory location actually storing the word at the top of the stack in main memory, the stack mechanism having means responsive to a predetermined program operator for inserting a mark word into the stack to mark a stack area to be used to store words for a procedure and having means responsive to another predetermined program operator directing the processor to enter a called from a calling procedure to transfer from the registers of the local memory to the corresponding locations of the main memory the part of the stack that was built up in the local memory by the calling procedure, thereby making those registers available for use in executing the called procedure.

Claim 16

The system as defined in claim 12 wherein the processor has an arithmetic unit and the stack mechanism includes a pair of registers coupled to the arithmetic unit to transfer for processing therein the top two words of a stack and stack adjusting means responsive to a predetermine operator to transfer the top two words of the stack to the pair of registers, whereby the words appear to pop-up, the stack adjusting means including means for indicating an overflow condition exists when a stack is built in the main memory while the local memory is full, the stack adjusting means responding to an indication that an overflow condition by transferring the top word of the stack from the main memory and responding to an indication that an overflow condition does not exist by transferring the top word of the stack from the local memory.

Claim 17

The system as defined in claim 13 wherein the stack adjusting means is operative in response to a predetermined operator to transfer out of the pair of register any words stored therein, whereby the words appear to be pushed down, the stack adjusting means responding to an indication that the local memory is full by transferring a word into the main memory and responding to an indication that the local memory is not full by transferring a word into the local memory.

Claim 18

ThE system as defined in claim 14 wherein the stack mechanism includes a register settable to store an indication of the main memory location used to store the first word of the stack to overflow out the local memory and into the local memory, and the stack adjusting means is operative to set the settable register during a push-down operation in response to indications that the local memory is full and that an overflow condition did not exist prior to the push-down operation.

Claim 19

The system as defined in claim 12 wherein the processor includes a register for storing an indication of a main memory location reserved for storing the mark word for the procedure that is currently being executed and a register for storing an indication of the location of a mark word for a procedure to be entered from the current procedure.

Claim 20

In a system having a main memory and a processor for processing a stack of information a part of which is stored in the main memory, a mark word being stored in a location of the memory at the base of each stack area used to store information words for a particular level of a program, the locations of the mark words serving as base addresses for relative addressing to exchange information between the processor and the main memory, the apparatus comprising an addressable local memory for the processor, the local memory having a plurality of registers for temporarily storing a part of the stack which is used for the current program level being executed and having means for indicating which of said plurality of registers stores the top word of the part of the stack stored therein; a register for storing an indication of a main memory location reserved for storing a word at the top of the stack, thereby serving to link the local memory to the main memory as a stack extension; means for storing a mark word in one of the registers of the local memory; a register for storing for the current program level a reference word which includes a level value and an index value, the level value indirectly indicating a base address and the index value indicating an address relative to the indicated base address; and means responsive to a reference word having a level value equal to the current program level for addressing the local memory relative to the location of the mark word stored therein with the index value, thereby enabling information to be recovered from the stack without accessing the main memory.

Claim 21

In a system having a main memory and a processor for processing a stack of information a part of which is stored in the main memory, a mark word being stored in a location of the memory at the base of each stack area used to store information words for a particular level of a program, the locations of the mark words serving as base addresses for relative addressing to exchange information between the processor and the main memory, the apparatus comprising an addressable local memory for the processor, the local memory having a plurality of registers for temporarily storing a part of the stack which is used for the current program level being executed and having means for indicating which of said plurality of registers stores the top word of the part of the stack stored therein; a register for storing an indication of a main memory location reserved for storing a word at the top of the stack, thereby serving to link the local memory to the main memory as a stack extension; means for storing a mark word in one of the registers of the local memory; a register for storing for the current program level a reference word which includes a level value and an index value, the level value indirectly indicating a base address and the index value indicating an address relative to the indicated base address; and means responsive to a reference word having a level value equal to the current program level for addressing the local memory relative to the location of the mark word stored therein with the index value, thereby enabling information to be recovered from the stack without accessing the main memory.