Prev: 49737 Up: Map Next: 49777
49767: Subtract Seven
Used by the routine at HandleBackspaceKey.
Steps the print column back by one cell and wraps when the column underflows.
SubtractSeven 49767 LD A,C Read the low byte of the count.
49768 SUB 7 Step back one character cell, wrapping to the previous row when the column underflows.
49770 LD C,A Store the result in the low byte of the count.
49771 RET NC Return when the column still fits on this row.
49772 DEC L Count down the low byte of the pointer.
49773 ADD A,8 Advance the result by 8.
49775 LD C,A Store the column.
49776 RET Return.
View the equivalent code in;
Prev: 49737 Up: Map Next: 49777