minnie.tuhs.org/unixen.tar/unixen/PDP-11/Trees/V6/usr/source/s5/printf.s

Text File | 1975-05-13 | 2.2 KB | 239 lines

/ C library -- printf


.globl    _printf

.globl    pfloat
.globl    pscien
.globl    _putchar

.globl    csv
.globl    cret

_printf:
    jsr    r5,csv
    sub    $126.,sp
    mov    4(r5),formp        / format
    mov    r5,r4
    add    $6,r4            / arglist
loop:
    movb    *formp,r0
    beq    1f
    inc    formp
    cmp    r0,$'%
    beq    2f
3:
    mov    r0,(sp)
    jsr    pc,*$_putchar
    br    loop
1:
    jmp    cret
2:
    clr    rjust
    clr    ndigit
    cmpb    *formp,$'-
    bne    2f
    inc    formp
    inc    rjust
2:
    jsr    r3,gnum
    mov    r1,width
    clr    ndfnd
    cmp    r0,$'.
    bne    1f
    jsr    r3,gnum
    mov    r1,ndigit
1:
    mov    sp,r3
    add    $4,r3
    mov    $swtab,r1
1:
    mov    (r1)+,r2
    beq    3b
    cmp    r0,(r1)+
    bne    1b
    jmp    (r2)
    .data
swtab:
    decimal;    'd
    octal;        'o
    hex;        'x
    float;        'f
    scien;        'e
    charac;        'c
    string;        's
    logical;    'l
    remote;        'r
    0;  0
    .text

decimal:
    mov    (r4)+,r1
    bge    1f
    neg    r1
    movb    $'-,(r3)+
    br    1f

logical:
    mov    (r4)+,r1
1:
    jsr    pc,1f
    br    prbuf
1:
    clr    r0
    div    $10.,r0
    mov    r1,-(sp)
    mov    r0,r1
    beq    1f
    jsr    pc,1b
1:
    mov    (sp)+,r0
    add    $'0,r0
    movb    r0,(r3)+
    rts    pc

charac:
    movb    (r4)+,(r3)+
    bne    1f
    dec    r3
1:
    movb    (r4)+,(r3)+
    bne    prbuf
    dec    r3
    br    prbuf

string:
    mov    ndigit,r1
    clr    r3
    mov    (r4),r2
1:
    tstb    (r2)+
    beq    1f
    inc    r3
    sob    r1,1b
1:
    mov    (r4)+,r2
    br    prstr

hex:
    mov    $1f,r2
    .data
1:
    -4; !17
    .text
    br    2f

octal:
    mov    $1f,r2
    .data
1:
    -3; !7
    .text
2:
    mov    (r4)+,r1
    beq    2f
    tst    ndigit
    beq    2f
    movb    $'0,(r3)+
2:
    clr    r0
    jsr    pc,1f
    br    prbuf
1:
    mov    r1,-(sp)
    ashc    (r2),r0
    beq    1f
    jsr    pc,1b
1:
    mov    (sp)+,r0
    bic    2(r2),r0
    add    $'0,r0
    cmp    r0,$'9
    ble    1f
    add    $'A-'0-10.,r0
1:
    movb    r0,(r3)+
    rts    pc

float:
    mov    ndigit,r0
    mov    ndfnd,r2
    jsr    pc,pfloat
    br    prbuf

scien:
    mov    ndigit,r0
    mov    ndfnd,r2
    jsr    pc,pscien
    br    prbuf

remote:
    mov    (r4)+,r4
    mov    (r4)+,formp
    jmp    loop

prbuf:
    mov    sp,r2
    add    $4,r2
    sub    r2,r3
prstr:
    mov    r4,-(sp)
    mov    $' ,-(sp)
    mov    r3,r4
    neg    r3
    add    width,r3
    ble    1f
    tst    rjust
    bne    1f
2:
    jsr    pc,*$_putchar
    sob    r3,2b
1:
    tst    r4
    beq    2f
1:
    movb    (r2)+,(sp)
    jsr    pc,*$_putchar
    sob    r4,1b
2:
    tst    r3
    ble    1f
    mov    $' ,(sp)
2:
    jsr    pc,*$_putchar
    sob    r3,2b
1:
    tst    (sp)+
    mov    (sp)+,r4
    jmp    loop

gnum:
    clr    ndfnd
    clr    r1
1:
    movb    *formp,r0
    inc    formp
    sub    $'0,r0
    cmp    r0,$'*-'0
    bne    2f
    mov    (r4)+,r0
    br    3f
2:
    cmp    r0,$9.
    bhi    1f
3:
    inc    ndfnd
    mul    $10.,r1
    add    r0,r1
    br    1b
1:
    add    $'0,r0
    rts    r3

.bss
width:    .=.+2
formp:    .=.+2
rjust:    .=.+2
ndfnd:    .=.+2
ndigit:    .=.+2