Resume processing function for the OS/2 operating system

In a computer system having a central processing unit (CPU) capable of operating in a protected mode and a real mode and operating under the OS/2 operating system, a resume processing method of saving and subsequently restoring system data indicative of the CPU's operating conditions in response to a power-off signal and a subsequent power-on signal, said resume processing method comprising the steps of:

• (a) initializing a resume processing driver to perform the following steps,
• (b) saving a first set of data associated with said OS/2 operating system indicative of OS/2's operating conditions responsive to said power-off signal,
• (c) saving a second set of data associated with said CPU, but not associated with said OS/2 operating system, indicative of said CPU's operating conditions in response to said power-off signal,
• (d) restoring said second set of data saved in step (c) responsive to a power-on signal, and
• (e) restoring said first set of data saved in step (b) responsive to a power-on signal, wherein step (b) comprises the steps of:
• (i) disabling interrupts associated with said CPU,
• (ii) saving registers, including a flag register, associated with said CPU,
• (iii) saving a programmable interrupt controller (PIC) mask associated with said CPU,
• (iv) disabling said PIC
• (v) saving said flag register on said stack, and
• (vi) saving a return address associated with said CPU onto a stack associated with said CPU, and
• (vii) resetting a floppy drive associated with said CPU if said floppy drive was active when said power-off signal was received.

A method, for use in a computer system having a CPU capable of operating in a protected mode and a real mode, the method for saving information indicative of the state of the CPU prior to a shut-down of the computer system, comprising the steps of:

• (1) receiving a power-down detection signal indicating that computer system information is to be saved;
• (2) saving protected mode information in response to said step (1);
• (3) switching the CPU from the protected mode to the real mode in response to said step (2);
• and
• (4) saving real mode information in response to said step (3).

A method for use in a computer system having a CPU capable of operating in a protected mode and a real mode, the method for restoring information indicative of the state of the CPU saved prior to a shut-down of the computer system, comprising the steps of:

• (1) receiving a power-up signal for indicating that computer system information is to be restored;
• (2) restoring real mode information in response to said step (1);
• (3) switching the CPU from the real mode to the protected mode in response to said step (2);
• and
• (4) restoring protected mode information in response to said step (3).

An apparatus, for use in a computer system having a BIOS and having a CPU capable of operating in a protected mode and a real mode, for saving information indicative of the state of the CPU prior to a shut-down of the computer system, comprising:

• power-down signal detection means for indicating, when the computer system is operating in the protected mode, that the state of the CPU is to be saved;
• protected mode saving means, responsive to said power-down signal detection means, for saving information indicative of the state of the CPU operating in the protected mode;
• a real mode switcher, responsive to said protected mode saving means, for switching the CPU from the protected mode to the real mode;
• and
• transfer control means, responsive to said real mode switcher, for activating a resume BIOS module residing in the BIOS,
• said resume BIOS module for saving information, while the CPU is operating in the real mode, indicative of the state of the CPU operating in the real mode.

An apparatus, for use in a computer system having a BIOS and having a CPU capable of operating in a protected mode and a real mode, for restoring information indicative of the state of the CPU saved prior to a shut-down of the computer system, comprising:

• power-up signal detection means for indicating that the state of the CPU is to be restored;
• activation means, responsive to said power-up signal detection means, for activating a resume BIOS module residing in the BIOS,
• said resume BIOS module for restoring information, while the CPU is operating in the real mode, indicative of the state of the CPU operating in the real mode, and for activating a protected mode switcher,
• said protected mode switcher for switching the CPU from the real mode to the protected mode;
• and
• protected mode restoring means, responsive to said protected mode switcher, for restoring information indicative of the state of the CPU operating in the protected mode.

An apparatus, for use in a computer system having a CPU capable of operating in a protected mode and a real mode, for saving information indicative of the state of the CPU prior to a shut-down of the computer system, comprising:

• power-down signal detection means for indicating that computer system information is to be saved;
• protected mode saving means, responsive to said power-down signal detection means, for saving protected mode information;
• a real mode switcher, responsive to said protected mode saving means, for switching the CPU from the protected mode to the real mode;
• real mode saving means, responsive to said real mode switcher, for saving real mode information.

An apparatus, for use in a computer system having a CPU capable of operating in a protected mode and a real mode, for restoring information indicative of the state of the CPU saved prior to a shut-down of the computer system, comprising:

• power-up signal detection means for indicating that computer system information is to be restored;
• real mode restoring means, responsive to said power-up signal detection means, for restoring real mode information;
• a protected mode switcher, responsive to said real mode restoring means, for switching the CPU from the real mode to the protected mode;
• protected mode restoring means, responsive to said real mode restoring means, for restoring protected mode information.

An apparatus, for use in a computer system having a CPU capable of operating in a protected mode and a real mode, the apparatus for saving information indicative of the state of the CPU prior to a shut-down of the computer system and for restoring information indicative of the state of the CPU saved prior to the shut-down of the computer system, comprising:

• power-down signal detection means for indicating that computer system information is to be saved;
• protected mode saving means, responsive to said power-down signal detection means, for saving protected mode information;
• a real mode switcher, responsive to said protected mode saving means, for switching the CPU from the protected mode to the real mode;
• real mode saving means, responsive to said real mode switcher, for saving real mode information;
• power-up signal detection means for indicating that computer system information is to be restored;
• real mode restoring means, responsive to said power-up signal detection means, for restoring real mode information;
• a protected mode switcher, responsive to said real mode restoring means, for switching the CPU from the real mode to the protected mode;
• protected mode restoring means, responsive to said real mode restoring means, for restoring protected mode information.