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6.12 Bit block transfer

Name:

»Bit block transfer«

Line-A number:

$A007

Syntax:

See 'Bindings for bit_blt'

Description:

This Line-A function copies between a rectangular source and destination block. For this the source area can be combined with a raster. Source and destination can be combined with one of 16 possible logical operations. This function also serves as the basis for the Line-A functions Text block transfer and Copy raster form.

For the parameters a structure of the type BITBLT has to be filled and passed in register A6.

The following logical combinations are available:

Operation	Function
0	D' = 0	Destination is background colour
1	D' = S & D
2	D' = S & D
3	D' = S
4	D' = S & D
5	D' = D
6	D' = S ^ D
7	D' = S \| D
8	D' = (S \| D)
9	D' = (S ^ D)
10	D' = D
11	D' = S \| D
12	D' = S
13	D' = S \| D
14	D' = (S & D)
15	D' = 1	Destination is foreground colour

D' is the destination after the combination, S and D are the source and destination before the combination. & is the logical AND combination, | is OR, ^ is the exclusive OR (XOR) combination, ! is a NOT inversion.

Return value:

The function does not have a return value.

Availability:

All TOS versions.

6.12.1 Bindings for bit_blt

Pure-C:	void bit_blt(BITBLT *bitblt);
Assembler:	movem.l D0-D2/A0-A2,-(A7) ; Save registers move.l bitblt,A6 ; Address BITBLT structure dc.w $A007 ; Line-A opcode movem.l (A7)+,D0-D2/A0-A2 ; Restore registers