PR#3
PREFIX /A2OSX.BUILD
LOMEM $A00
INC 1
AUTO 6
				.LIST OFF	
*--------------------------------------
HIS.Init		>LDYAI 256				Get a buffer for History
				>SYSCALL GetMem0.YA
				bcs .9

				txa
				>STA.G HIS.hBuf
				
				lda #0
				>STA.G HIS.BufIndex
				>STA.G HIS.BufEnd
.9				rts
*--------------------------------------
HIS.Add			>LDA.G HIS.hBuf
				beq .9
				
				>SYSCALL GetMemPtr.A
				>STYA ZPPTR1
				
.10				>LDA.G HIS.BufEnd		
				
.11				sec						add len+1
				adc CmdBuflen			CmdBuffer length
				bcc .2					enough room
				
				lda (ZPPTR1)			get len of oldest string
				sec
				adc ZPPTR1
				sta ZPPTR2
				lda ZPPTR1+1
				adc #0
				sta ZPPTR2+1
				
				ldy #$FF
				
.1				iny
				lda (ZPPTR2),y			move back until ending 0 found
				sta (ZPPTR1),y
				bne .1
				
				tya
				
				>STA.G HIS.BufEnd		mark new end of history
				bra .11					retry....
				
.2				tax						keep new HIS.BufEnd

				tay
				lda #0
				sta (ZPPTR1),y			set ending 0

				>LDA.G HIS.BufEnd		save old END
				pha
				
				txa						get back new END

				>STA.G HIS.BufIndex		set it as new IDX
				>STA.G HIS.BufEnd		set new HIS.BufEnd
				
				pla						get back old END
				clc
				adc ZPPTR1
				sta ZPPTR1
				bcc .3
				inc ZPPTR1+1
				
.3				ldy #0
				
.4				lda (ZPCMDBuf),y
				beq .5
				
				iny
				sta (ZPPTR1),y
				iny
				bra .4
				
.5				tya
				sta (ZPPTR1)
.9				rts
*--------------------------------------
HIS.GetPrev		>LDA.G HIS.hBuf
				beq HISTORY.RTS
				
				tax
				
				>LDA.G HIS.BufEnd
				beq HISTORY.RTS			empty history,nothing to do
				>LDA.G HIS.BufIndex
				beq HISTORY.RTS			already oldest,nothing to do
				
				txa

				>SYSCALL GetMemPtr.A
				>STYA ZPPTR1
				
				lda #0
				
.1				tax
				tay
				sec
				adc (ZPPTR1),y
				bcs History.RTS			out of buffer
				
				ldy #HIS.BufIndex
				cmp (pData),y
				bne .1					reached current index
				
.2				txa
				>STA.G HIS.BufIndex		set new index
				bra HIS.SetBuf
History.RTS		rts
*--------------------------------------
HIS.GetNext		>LDA.G HIS.hBuf
				beq HISTORY.RTS
				
				tax
				
				>LDA.G HIS.BufEnd
				beq HISTORY.RTS			empty history,nothing to do
				>CMP.G HIS.BufIndex
				beq HISTORY.RTS			already oldest,nothing to do
				
				txa
	
				>SYSCALL GetMemPtr.A
				>STYA ZPPTR1

				>LDA.G HIS.BufIndex
				tay
				sec
				adc (ZPPTR1),y			add length+1 of current line in history
				>STA.G HIS.BufIndex
				
				>CMP.G HIS.BufEnd
				bne HIS.SetBuf
				jmp CmdLine.CLR		end of history, just blank buffer
*--------------------------------------
HIS.SetBuf		jsr CmdLine.CLR

				>LDA.G HIS.BufIndex
				tay						keep length of string
				
				clc
				adc ZPPTR1
				sta ZPPTR1
				bcc .1
				inc ZPPTR1+1
				
.1				lda (ZPPTR1),y
				sta (ZPCMDBuf),y
				dey
				bpl .1
				jmp CmdLine.SET
*--------------------------------------
HIS.Quit		>LDA.G HIS.hBuf
				beq .9
				>SYSCALL FreeMem.A
.9				rts
*--------------------------------------
MAN
SAVE /A2OSX.SRC/SBIN/SHELL.S.HIS
LOAD /A2OSX.SRC/SBIN/SHELL.S
ASM