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Length: 1792 (0x700)
Types: TextFile
Names: »MPRL.MAC«
└─⟦01b5c9619⟧ Bits:30005906 Microsoft Multiplan v1.05 og HELP
└─ ⟦this⟧ »MPRL.MAC«
; ; ; Title Multiple-Precision Rotate Left ; Name: MPRL ; ; ; Purpose: Rotate left a multi-byte operand N bits ; ; Entry: Register pair HL = base address of operand ; Register B = lenght of operand in bytes ; Register C = number of bits to rotate ; ; The operand is stored with ARRAYÆ0Å as its ; least significant byte and ARRAYÆLENGHT-1Å ; its most significant byte, where ARRAY ; is its base address. ; ; Exit: Operand rotated left ; CARRY := last bit shifted from lmost ; significant position ; ; Registers used: AF,BC,DE,HL ; ; Time: 104 cycles overhead plus ; ((34 * lenght) + 58) cycles per rotate ; ; Size: Program 35 bytes ; ; ; MPRL: ;Exit if number of rotates or lenght of operand is 0 ;Or clears carry in eighter case ld a,c or a ret z ;Return if number of rotates is 0 ld a,b or a ret z ;Return if lenght of operand is 0 ;Calculate address of most significant (last) byte push hl ld e,b ;Address of MSB = base + lenght - 1 ld d,0 add hl,de dec hl push hl pop ix ;IX points to MSB (first byte) pop hl ;HL points to LSB (last byte) ;C = number of rotates ;A = lenght of operand ;Loop on number of rotates to perform ;CARRY = most significant bit of entire operand loop: ld b,(ix+0) ;Get MSB rl b ;CARRY = bit 7 of MSB ld b,a ;B = lenght of operand in bytes ld e,l ;Save address of MSB ld d,h ;Rotate bytes left starting with least significant rllp: rl (hl) ;Rotate a byte left inc hl ;Increment to more significant byte djnz rllp ld l,e ;Restore address of LSB ld h,d dec c ;Decrement number of rotates jr nz,loop ret «eof»