June 25, 2006 Problem with asm and short | ||||
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I think this program: ---------------------------- import std.stdio; void main() { short* s = new short[3]; s[0] = 1; s[1] = 2; s[2] = 3; int a = 0; asm { mov EAX, s; mov ECX, [EAX]; mov a, ECX; } writefln("%s", a); } ---------------------------- should output 1, but it outputs 131073 (garbage). However, if instead of [EAX] you write [EAX + 4] it outputs 3 (and with [EAX + 2] garbage again). Am I doing something wrong or this is a bug? If the array is of ints, the programs works OK. |
June 25, 2006 Re: Problem with asm and short | ||||
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Posted in reply to Ary Manzana | Ary Manzana wrote: > asm { > mov EAX, s; > mov ECX, [EAX]; > mov a, ECX; > } > > should output 1, but it outputs 131073 (garbage). However, if instead of [EAX] > you write [EAX + 4] it outputs 3 (and with [EAX + 2] garbage again). Am I doing > something wrong or this is a bug? > > If the array is of ints, the programs works OK. Shorts are 16bit, ECX is 32bit. 'mov ECX, [EAX]' copies 32bits from the [EAX] address to ECX, while you should only copy 16 (a short/word). Try this: asm { mov EAX, s; xor ECX, ECX; mov CX, [EAX]; mov a, ECX; } -- Tomasz Stachowiak /+ a.k.a. h3r3tic +/ |
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