BIT b,r

Operation

     __
Z <- rb

Mnemonic

BIT

Operands

b,r

b7b6b5b4b3b2b1b0
1 1 0 0 1 0 1 1$CB
0 1 br

Description

This instruction tests bit b in register r and sets the Z flag accordingly. In the assembled object code, operands b and r are specified as follows:

Bit TestedbRegrHexRegrHexRegrHexRegrHexRegrHexRegrHexRegrHex
0000A111$47B000$40C001$41D010$42E011$43H100$44L101$45
1001A111$4FB000$48C001$49D010$4AE011$4BH100$4CL101$4D
2010A111$57B000$50C001$51D010$52E011$53H100$54L101$55
3011A111$5FB000$58C001$59D010$5AE011$5BH100$5CL101$5D
4100A111$67B000$60C001$61D010$62E011$63H100$64L101$65
5101A111$6FB000$68C001$69D010$6AE011$6BH100$6CL101$6D
6110A111$77B000$70C001$71D010$72E011$73H100$74L101$75
7111A111$7FB000$78C001$79D010$7AE011$7BH100$7CL101$7D

Condition Bits Affected

Sis unknown.
Zis set if specified bit is 0, otherwise it is reset.
His set.
P/Vis unknown
Nis reset.
Cis not affected.

Example

If bit 2 in Register B contains 0, then upon the execution of

	BIT	2,B

the Z flag in the F Register contains 1, and bit 2 in Register B remains at 0. Bit 0 in Register B is the least-significant bit.