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The Hourglass module will change the pointer shape to that of an Hourglass. You can optionally also display a percentage figure and two "LED" indicators for status information.

The Hourglass interface is via the following SWI's

Hourglass_On &406C0

Entry:
Exit:

This turns on the Hourglass. Although control return immediately there is a delay of 1/3 of a second before the Hourglass becomes visible. Thus the client can bracket an operation by Hourglass_On/Hourglass_Off and the hourglass will only be displayed if the operation takes longer than 1/3 of a second. (For delays other than the default see Hourglass_Start).

Hourglass_On's are nestable. If the Hourglass is already visible then a count is incremented and the Hourglass will remain visible until an equivalent number of Hourglass_Off's are done.

Hourglass_Off &406C1

Entry:
Exit:

This will turn off the Hourglass, unless of course there are nested Hourglass_On calls in which case the Hourglass stays visible until an equal number of Hourglass_Off calls are made.

When the Hourglass is removed the pointer number and colours are restored to those in use at the first Hourglass_On.

Note that cursor shapes 3 and 4 are used (ie corrupted!) by the Hourglass, but users should not have been using these anyway.

Hourglass_Smash &406C2

Entry:
Exit:

Will turn off the Hourglass immediately taking no notice of nested Hourglass_On's. A last ditch call for when you are sure neither you, nor anyone else, should be displaying an Hourglass.

Hourglass_Start &406C3

Entry:
R0 = Delay before startup in centi-seconds.
Exit:

Similar to Hourglass_On, except you can provide your own startup delay.

A delay of zero can be used to suppress the Hourglass, so future Hourglass_On and Hourglass_Start calls have no effect. This only applies if the Hourglass is currently off. The condition is terminated by the matching Hourglass_Off, or by an Hourglass_Smash.

Hourglass_Percentage &406C4

Entry:
R0 = (0-99) Percentage to display
otherwise turn off Percentage
Exit:

The user can display a Percentage below the Hourglass. If in the range 0-99 it is displayed, values outside this range turn off the percentage.

The initial condition of an Hourglass is to have Percentages turned off.

Hourglass_LEDs &406C5

Entry:
R0, R1 setup LEDs
NewLEDs = (OldLEDs AND R1) XOR R0
Exit:
R0 = OldLEDs

The are two display indicators above the Hourglass which can be used to display status information. These correspond to bits 0,1 of the LEDs word. Bit set indicates indicator on.

The default condition is all indicators off.