The Coreq Pseudo-Variable; The Get87 Command - Intel l2ICE User Manual

The COREQ Pseudo-Variable

The COREQ pseudo-variable enables or disables an external numeric extension and is specific
to the 80286 probe. When COREQ = TRUE, the 80286 probe recognizes its PEREQ and
PEACK lines. Setting COREQ = FALSE disables the external numeric extension, and the
80286 probes does not recognized the PEREQ and PEACK lines.

The GET87 Command

The GET87 command is specific to the 8086/8088 and 80186/80188 probes. You must enter
the GET87 command to tell the PICE system that an 8087 coprocessor is present. The 8087
must be enabled (COENAB must be TRUE) for the PICE system to execute the GET87
command.
The following restrictions apply when you use the GET87 command with an external
coprocessor:
• The probe must not be emulating and CPMODE must be 2.
• Include with the GET87 command the starting address of a 110-byte buffer. The PICE
system uses this area as an intermediate buffer in saving and restoring the 8087 register
data. The original contents of this buffer are preserved between save and restore opera­
tions. User's data is restored in the buffer after the GET87 command is entered. This
buffer must be mapped to USER and not specified as read-only.
The following restrictions apply when using the GET87 command with an internal coprocessor
(8086/8088 probe only):
• The probe must not be emulating. The value of CPMQDE is not significant.
• Do not include an address with the GET87 command. The PICE system uses reserved
system memory rather than USER memory for the register buffer. If you do include an
address, the PICE system ignores it. •
• The PICE system always loads the actual 8087 registers with the values from the buffer
when you resume emulation after modifying one or more 8087 registers.
5-4
Coprocessor Support