; Project name : Assembly Library ; Description : Functions for register operations. ; Section containing code SECTION .text ;-------------------------------------------------------------------- ; Registers_ExchangeDSSIwithESDI ; Parameters ; Nothing ; Returns: ; DS:SI and ES:DI are exchanged. ; Corrupts registers: ; Nothing ;-------------------------------------------------------------------- ALIGN JUMP_ALIGN Registers_ExchangeDSSIwithESDI: push ds push es pop ds pop es xchg si, di ret ;-------------------------------------------------------------------- ; Registers_CopySSBPtoESDI ; Registers_CopySSBPtoDSSI ; Registers_CopyDSSItoESDI ; Registers_CopyESDItoDSSI ; Parameters ; Nothing ; Returns: ; Copies farm pointer to different segment/pointer register pair ; Corrupts registers: ; Nothing ;-------------------------------------------------------------------- ALIGN JUMP_ALIGN Registers_CopySSBPtoESDI: COPY_SSBP_TO_ESDI ret %ifndef EXCLUDE_FROM_XTIDE_UNIVERSAL_BIOS ALIGN JUMP_ALIGN Registers_CopySSBPtoDSSI: COPY_SSBP_TO_DSSI ret ALIGN JUMP_ALIGN Registers_CopyDSSItoESDI: COPY_DSSI_TO_ESDI ret ALIGN JUMP_ALIGN Registers_CopyESDItoDSSI: COPY_ESDI_to_DSSI ret %endif ;-------------------------------------------------------------------- ; Registers_NormalizeESSI ; Registers_NormalizeESDI ; Parameters ; DS:SI or ES:DI: Ptr to normalize ; Returns: ; DS:SI or ES:DI: Normalized pointer ; Corrupts registers: ; AX, CX ; ; Inline of NORMALIZE_FAR_POINTER so that we can share the last 2/3 of the ; routine with Registers_NormalizeFinish. ; ;-------------------------------------------------------------------- ALIGN JUMP_ALIGN Registers_NormalizeESSI: mov cx, si and si, byte 0fh jmp Registers_NormalizeFinish ALIGN JUMP_ALIGN Registers_NormalizeESDI: mov cx, di and di, byte 0fh ;;; fall-through ALIGN JUMP_ALIGN Registers_NormalizeFinish: eSHR_IM cx, 4 mov ax, es add ax, cx mov es, ax ret ;-------------------------------------------------------------------- ; Registers_SetZFifNullPointerInDSSI (commented to save bytes) ; Parameters ; DS:SI: Far pointer ; Returns: ; ZF: Set if NULL pointer in DS:SI ; Corrupts registers: ; Nothing ;-------------------------------------------------------------------- ;ALIGN JUMP_ALIGN ;Registers_SetZFifNullPointerInDSSI: ; push ax ; mov ax, ds ; or ax, si ; pop ax ; ret