| Routines

2580: THE 'SCANNING ATTRIBUTES' SUBROUTINE

Used by the routine at S_ATTR.
S_ATTR_S | 2580 | CALL STK_TO_BC | x to C, y to B. Again, 0<=x<=23; 0<=y<=31.
| 2583 | LD A,C | x is copied to A and the number 32*(x mod 8)+y is formed in A. 32*(x mod 8)+INT (x/8) is also copied to C.
| 2584 | RRCA
| 2585 | RRCA
| 2586 | RRCA
| 2587 | LD C,A
| 2588 | AND $E0
| 258A | XOR B
| 258B | LD L,A | L holds low byte of attribute address.
| 258C | LD A,C | 32*(x mod 8)+INT (x/8) is copied to A.
| 258D | AND $03 | 88+INT (x/8) is formed in A.
| 258F | XOR $58
| 2591 | LD H,A | H holds high byte of attribute address.
| 2592 | LD A,(HL) | The attribute byte is copied to A.
| 2593 | JP STACK_A | Exit, stacking the required byte.