diff options
Diffstat (limited to 'src/syscall.asm')
| -rw-r--r-- | src/syscall.asm | 146 |
1 files changed, 134 insertions, 12 deletions
diff --git a/src/syscall.asm b/src/syscall.asm index 5ed3d6f..f149a76 100644 --- a/src/syscall.asm +++ b/src/syscall.asm @@ -50,6 +50,10 @@ SyscallTable: dw sys_putb ; 13 PUTB dw sys_list ; 14 LIST dw sys_remove ; 15 REMOVE + dw sys_putc ; 16 PUTC + dw sys_setin ; 17 SETIN + dw sys_setout ; 18 SETOUT + dw sys_lookup ; 19 LOOKUP ; ----------------------------------------------------------------------------- sys_nosys: @@ -64,33 +68,151 @@ sys_write: ld a, b or a ret z ; len 0 - ld c, b ; C = remaining .loop ld a, [de] - call PutChar + push de + push bc + ld e, a + call KPutc ; route the byte to this process's stdout + pop bc + pop de inc de - dec c + dec b jr nz, .loop - ld a, b ; return len ret ; ----------------------------------------------------------------------------- -; sys_read() -> A = one input byte from the console (blocking). -; Uses an external-clock serial transfer as a clean RX: it completes only when -; the host has a byte (no stdout echo). While waiting we yield so other procs -; run. Preserves BC/DE/HL (the context switch saves/restores them). +; CurStdin / CurStdout -> A = current process PROC_STDIN / PROC_STDOUT ; ----------------------------------------------------------------------------- -sys_read: +CurStdin: + ld a, [wCurProc] + add PROC_STDIN + ld l, a + ld a, [wCurProc+1] + adc 0 + ld h, a + ld a, [hl] + ret +CurStdout: + ld a, [wCurProc] + add PROC_STDOUT + ld l, a + ld a, [wCurProc+1] + adc 0 + ld h, a + ld a, [hl] + ret + +; ----------------------------------------------------------------------------- +; KGetc -> A = byte, CF set on EOF. Reads this process's stdin (console/file). +; ----------------------------------------------------------------------------- +KGetc:: + call CurStdin + cp STD_CONSOLE + jr z, .console + ld b, a + jp sys_getb ; B=fd -> A=byte, CF=EOF +.console .poll ld a, $80 - ld [rSC], a ; request a byte (external clock) + ld [rSC], a ld a, [rSC] bit 7, a - jr z, .got ; bit7 clear => transfer completed - call SchedYield ; nothing yet: let others run, then retry + jr z, .got + call SchedYield jr .poll .got ld a, [rSB] + and a ; CF = 0 + ret + +; ----------------------------------------------------------------------------- +; KPutc(E = byte) - write to this process's stdout (console/file). +; ----------------------------------------------------------------------------- +KPutc:: + ld a, e + ld [wKChar], a + call CurStdout + cp STD_CONSOLE + jr z, .console + ld b, a ; fd + ld a, [wKChar] + ld e, a + jp sys_putb ; B=fd, E=byte +.console + ld a, [wKChar] + ld [rSB], a + ld a, $81 + ld [rSC], a + ret + +; ----------------------------------------------------------------------------- +; sys_putc(E = byte), sys_setin/sys_setout(B = fd) +; ----------------------------------------------------------------------------- +sys_putc: + call KPutc + ret +sys_setin: + ld a, [wCurProc] + add PROC_STDIN + ld l, a + ld a, [wCurProc+1] + adc 0 + ld h, a + ld a, b + ld [hl], a + ret +sys_setout: + ld a, [wCurProc] + add PROC_STDOUT + ld l, a + ld a, [wCurProc+1] + adc 0 + ld h, a + ld a, b + ld [hl], a + ret + +; ----------------------------------------------------------------------------- +; sys_lookup(DE = name) -> A = program id, or $FF if not a known command. +; ----------------------------------------------------------------------------- +sys_lookup: + ld h, d + ld l, e ; HL = query name + ld de, NameTable +.l + ld a, [de] + or a + jr z, .none + push hl + push de + call StrEqual ; HL=query vs DE=table name -> Z if equal + pop de + pop hl + jr z, .match + call SkipName ; DE -> NUL + inc de ; -> id + inc de ; -> next entry + jr .l +.match + call SkipName + inc de ; -> id + ld a, [de] + ret +.none + ld a, $FF + ret + +; ----------------------------------------------------------------------------- +; sys_read() -> A = one input byte from the console (blocking). +; Uses an external-clock serial transfer as a clean RX: it completes only when +; the host has a byte (no stdout echo). While waiting we yield so other procs +; run. Preserves BC/DE/HL (the context switch saves/restores them). +; ----------------------------------------------------------------------------- +sys_read: + call KGetc ; A=byte, CF=EOF (file); console EOF is $04 + ret nc + ld a, $04 ; file EOF -> EOT ret ; ----------------------------------------------------------------------------- |