intovfrt.asm

来自「开放源码的编译器open watcom 1.6.0版的源代码」· 汇编 代码 · 共 78 行

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//
// intovfrt       : Integer add/sub/mul with overflow check
//

#include "axp_regs.h"

.globl  __Add
// .ent __Add
__Add:
        ldl     t0, (a0)                // load argument 1
        ldl     t1, (a1)                // load argument 2
        addl    t0, t1, t2              // add 32 bit integers
        addq    t0, t1, t3              // add 64 bit integers
        cmpeq   t2, t3, v0              // check if they are the same,
        xor     v0, 1, v0               // ...
        stl     t2, (a0)                // Save result
        ret     zero, (ra)              // Use same routine as to switch in
// .end __Add

.globl  __Sub
// .ent __Sub
__Sub:
        ldl     t0, (a0)                // load argument 1
        ldl     t1, (a1)                // load argument 2
        subl    t0, t1, t2              // multiply 32 bit integers
        subq    t0, t1, t3              // multiply 64 bit integers
        cmpeq   t2, t3, v0              // check if they are the same,
        xor     v0, 1, v0               // ...
        stl     t2, (a0)                // Save result
        ret     zero, (ra)              // Use same routine as to switch in
// .end __Sub

.globl  __Mul
// .ent __Mul
__Mul:
        ldl     t0, (a0)                // load argument 1
        ldl     t1, (a1)                // load argument 2
        mull    t0, t1, t2              // multiply 32 bit integers
        mulq    t0, t1, t3              // multiply 64 bit integers
        cmpeq   t2, t3, v0              // check if they are the same,
        xor     v0, 1, v0               // ...
        stl     t2, (a0)                // Save result
        ret     zero, (ra)              // Use same routine as to switch in
// .end __Mul