Spectrum ROM: Routine at 35BF

35BF: THE 'STK-PNTRS' SUBROUTINE

Used by the routines at CALCULATE, strs_add, val and read_in.

This subroutine resets the HL register pair to point to the first byte of the 'last value', i.e. STKEND-5, and the DE register pair to point one past the 'last value', i.e. STKEND.

Output
DE	STKEND
HL	STKEND-5

STK_PNTRS

35BF

LD HL,($5C65)

Fetch the current value of STKEND.

35C2

LD DE,$FFFB

Set DE to -5, two's complement.

35C5

PUSH HL

Stack the value for STKEND.

35C6

ADD HL,DE

Calculate STKEND-5.

35C7

POP DE

DE now holds STKEND and HL holds STKEND-5.

35C8

RET