Annotation of OpenXM_contrib/gnuplot/pcgraph.asm, Revision 1.1
1.1 ! maekawa 1: TITLE PC graphics module
! 2: ; uses LINEPROC.MAC
! 3:
! 4: ; Michael Gordon - 8-Dec-86
! 5: ;
! 6: ; Certain routines were taken from the Hercules BIOS of Dave Tutelman - 8/86
! 7: ; Others came from pcgraph.asm included in GNUPLOT by Colin Kelley
! 8: ;
! 9: ; modified slightly by Colin Kelley - 22-Dec-86
! 10: ; added header.mac, parameterized declarations
! 11: ; added dgroup: in HVmodem to reach HCh_Parms and HGr_Parms - 30-Jan-87
! 12: ;
! 13: ; modified and added to for use in plot(3) routines back end.
! 14: ; Gil Webster.
! 15: ;
! 16: ; Assemble with masm ver. 4.
! 17:
! 18: include header.mac
! 19:
! 20: if1
! 21: include lineproc.mac
! 22: endif
! 23:
! 24: GPg1_Base equ 0B800h ; Graphics page 1 base address
! 25:
! 26: extrn _inter:far
! 27:
! 28: _text segment
! 29:
! 30: public _PC_line, _PC_color, _PC_mask, _PC_curloc, _PC_puts, _Vmode
! 31: public _erase, _save_stack, _ss_interrupt
! 32:
! 33: pcpixel proc near
! 34: ror word ptr linemask,1
! 35: jc cont
! 36: ret
! 37: cont:
! 38: push ax
! 39: push bx
! 40: push cx
! 41: push dx
! 42: push bp
! 43: mov cx,ax ; x
! 44: mov dx,bx ; y
! 45: mov ah,0ch ; ah = write pixel
! 46: mov al,byte ptr color
! 47:
! 48: mov bh, 0 ; page 0
! 49: int 10h
! 50: pop bp
! 51: pop dx
! 52: pop cx
! 53: pop bx
! 54: pop ax
! 55: ret
! 56: pcpixel endp
! 57:
! 58: lineproc _PC_line, pcpixel
! 59:
! 60: ;
! 61: ; erase - clear page 1 of the screen buffer to zero (effectively, blank
! 62: ; the screen)
! 63: ;
! 64: beginproc _erase
! 65: push es
! 66: push ax
! 67: push cx
! 68: push di
! 69: mov ax, GPg1_Base
! 70: mov es, ax
! 71: xor di, di
! 72: mov cx, 4000h
! 73: xor ax, ax
! 74: cld
! 75: rep stosw ; zero out screen page
! 76: pop di
! 77: pop cx
! 78: pop ax
! 79: pop es
! 80: ret
! 81: _erase endp
! 82:
! 83: beginproc _PC_color
! 84: push bp
! 85: mov bp,sp
! 86: mov al,[bp+X] ; color
! 87: mov byte ptr color,al
! 88: pop bp
! 89: ret
! 90: _PC_color endp
! 91:
! 92: beginproc _PC_mask
! 93: push bp
! 94: mov bp,sp
! 95: mov ax,[bp+X] ; mask
! 96: mov word ptr linemask,ax
! 97: pop bp
! 98: ret
! 99: _PC_mask endp
! 100:
! 101: beginproc _Vmode
! 102: push bp
! 103: mov bp,sp
! 104: push si
! 105: push di
! 106: mov ax,[bp+X]
! 107: int 10h
! 108: pop di
! 109: pop si
! 110: pop bp
! 111: ret
! 112: _Vmode endp
! 113:
! 114: beginproc _PC_curloc
! 115: push bp
! 116: mov bp,sp
! 117: mov dh, byte ptr [bp+X] ; row number
! 118: mov dl, byte ptr [bp+X+2] ; col number
! 119: mov bh, 0
! 120: mov ah, 2
! 121: int 10h
! 122: pop bp
! 123: ret
! 124: _PC_curloc endp
! 125:
! 126: ;
! 127: ; thanks to watale!broehl for finding a bug here--I wasn't pushing BP
! 128: ; and reloading AH before INT 10H, which is necessary on genuine IBM
! 129: ; boards...
! 130: ;
! 131: beginproc _PC_puts
! 132: push bp
! 133: mov bp,sp
! 134: push si
! 135: mov bl,byte ptr color
! 136: mov si,[bp+X] ; offset
! 137:
! 138: ifdef LARGE_DATA
! 139: mov es,[bp+X+2] ; segment if large or compact data model
! 140: endif
! 141:
! 142: puts2:
! 143:
! 144: ifdef LARGE_DATA
! 145: mov al,es:[si]
! 146: else
! 147: mov al,[si]
! 148: endif
! 149: or al,al
! 150: jz puts3
! 151: mov ah,0eh ; write TTY char
! 152: int 10h
! 153: inc si
! 154: jmp short puts2
! 155: puts3: pop si
! 156: pop bp
! 157: ret
! 158: _PC_puts endp
! 159:
! 160:
! 161: ; int kbhit();
! 162: ; for those without MSC 4.0
! 163: ; Use BIOS interrupt 16h to determine if a key is waiting in the buffer.
! 164: ; Return nonzero if so.
! 165: ;
! 166:
! 167: beginproc _kbhit
! 168: mov ah, 1 ; function code 1 is keyboard test
! 169: int 16h ; keyboard functions
! 170: jnz kbfin ; Exit if char available
! 171: xor ax, ax ; No char: return zero.
! 172: kbfin: ret
! 173: _kbhit endp
! 174:
! 175:
! 176: ; _save_stack and _ss_interrupt are needed due to a bug in the MSC 4.0
! 177: ; code when run under MS-DOS 3.x. Starting with 3.0, MS-DOS automatically
! 178: ; switches to an internal stack during system calls. This leaves SS:SP
! 179: ; pointing at MS-DOS's stack when the ^C interrupt (INT 23H) is triggered.
! 180: ; MSC should restore its own stack before calling the user signal() routine,
! 181: ; but it doesn't.
! 182: ;
! 183: ; Presumably this code will be unnecessary in later releases of the compiler.
! 184: ;
! 185:
! 186: ; _save_stack saves the current SS:SP to be loaded later by _ss_interrupt.
! 187: ;
! 188:
! 189: beginproc _save_stack
! 190: mov ax,ss
! 191: mov cs:save_ss,ax
! 192: mov ax,sp
! 193: mov cs:save_sp,ax
! 194: ret
! 195: _save_stack endp
! 196:
! 197:
! 198: ; _ss_interrupt is called on ^C (INT 23H). It restores SS:SP as saved in
! 199: ; _save_stack and then jumps to the C routine interrupt().
! 200: ;
! 201: beginproc _ss_interrupt
! 202: cli ; no interrupts while the stack is changed!
! 203: mov ax,-1 ; self-modifying code again
! 204: save_ss equ this word - 2
! 205: mov ss,ax
! 206: mov sp,-1 ; here too
! 207: save_sp equ this word - 2
! 208: sti
! 209: jmp far ptr _inter; now it's safe to call the real routine
! 210: _ss_interrupt endp
! 211:
! 212:
! 213: _text ends
! 214:
! 215:
! 216: const segment
! 217: linemask dw -1
! 218: color db 1
! 219: const ends
! 220:
! 221: end
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