[_CDCSL_93-16_]<1>Cedar>release>Breakpoints>obsolete>SPARCBreakpoint.mesa

SPARCBreakpoint.mesa

Peter B. Kessler, March 29, 1990 10:30 am PST

DIRECTORY

SPARCArchitecture,

SPARCManger;

SPARCBreakpoint: CEDAR DEFINITIONS ~ {

Patches can't be monitored, since the processor executes out of them. My accesses of the patches and the pc's executing in them are races. That isn't a problem because the pc's never get to the patches until I'm done setting them up (fortunately), and I don't clear the patch. Clearing a breakpoint is just putting the instruction back, since you can't tell when the pc (or several of them) are done with the patch (that's is a garbage collection problem).

This closureCaller is for SPARC's: it includes pushing an extra register window to avoid some register saving and to allocate space for saving the rest of the registers.

save %sp, -(spOffset+stackAllocationForCallee+registerSaveArea), %sp

-- allocate a register window and a register save area.

call ←save←regs

add %sp, spOffset+stackAllocationForCallee, %o0

-- save←regs(@registerSaveArea).

sethi %hi(clientData), %o0

call clientProc

or %lo(clientData), %o0

-- clientProc(clientData).

call ←restore←regs

add %sp, spOffset + stackAllocationForCallee, %o0

-- restore←regs(@registerSaveArea).

restore %sp, +(spOffset+stackAllocationForCallee+registerSaveArea), %sp

-- deallocate the register window and register save area.

Constants.

registerSaveArea: NAT ~ 64 * BYTES[SPARCArchitecture.SPARCContents];

64 words for saving the rest of the registers.

Types.

Patches are self-describing, in that they include the address of the replaced instruction (in the header) and the replaced instruction (relocated into the patch).

PatchStruct: TYPE ~ MACHINE DEPENDENT RECORD [

closureCaller: ClosureCaller,

manger: SPARCManger.Manger

];

ClosureCaller: TYPE ~ MACHINE DEPENDENT RECORD [

save: SPARCArchitecture.SPARCInstruction,

callSaveRegs: SPARCArchitecture.SPARCInstruction,

argSaveAreaOnce: SPARCArchitecture.SPARCInstruction,

in the delay slot.

argHiClientData: SPARCArchitecture.SPARCInstruction,

callClientProc: SPARCArchitecture.SPARCInstruction,

argLoClientData: SPARCArchitecture.SPARCInstruction,

in the delay slot.

callRestoreRegs: SPARCArchitecture.SPARCInstruction,

argSaveAreaAgain: SPARCArchitecture.SPARCInstruction,

in the delay slot.

restore: SPARCArchitecture.SPARCInstruction

];