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fix the detail for PC-relative relocations and add explanation #58

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fix the detail for PC-relative relocations and add explanation #58

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24 changes: 13 additions & 11 deletions docs/LoongArch-ELF-ABI-CN.adoc
View file
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Original file line number Diff line number Diff line change
Expand Up @@ -698,7 +698,8 @@ v2.00
|71
|R_LARCH_PCALA_HI20
|相对 PC 偏移 32/64 位的 [31 ... 12] 位
|`+(*(uint32_t *) PC) [24 ... 5] = (((S+A) & ~0xfff) - (PC & ~0xfff)) [31 ... 12]+`
|`+(*(uint32_t *) PC) [24 ... 5] = ((hi20(S+A) - (PC & ~0xfff)) [31 ... 12]+` footnote:foot_hi20[`hi20(x)` 定义为 `(x + 0x800) & ~0xfff`。`+ 0x800`
使得结果能够和视为 12 位带符号数的 `x & 0xfff` 相加。]

`+注意：所有相对 PC 偏移计算都不包含低12位。+`

Expand All @@ -710,17 +711,18 @@ v2.00
|73
|R_LARCH_PCALA64_LO20
|相对 PC 偏移 64 位的 [51 ... 32] 位
|`+(*(uint32_t *) PC) [24 ... 5] = (S+A - (PC & ~0xffffffff)) [51 ... 32]+`
|`+(*(uint32_t *) PC) [24 ... 5] = (hi32(S+A) - (PC & ~0xffffffff)) [51 ... 32]+` footnote:foot_hi32[`hi32(x)` 定义为 `x - ((x & 0x800) << 21)`。`-((x & 0x800) << 21)` 使得结果能够和 `x & 0xfff` 视为 12 位带符号数并扩展到 32
位的结果，以及 `hi20(x)` 相加。]

|74
|R_LARCH_PCALA64_HI12
|相对 PC 偏移 64 位的 [63 ... 52] 位
|`+(*(uint32_t *) PC) [21 ... 10] = (S+A - (PC & ~0xffffffff)) [63 ... 52]+`
|`+(*(uint32_t *) PC) [21 ... 10] = (hi32(S+A) - (PC & ~0xffffffff)) [63 ... 52]+` footnote:foot_hi32[]

|75
|R_LARCH_GOT_PC_HI20
|GOT 表项相对 PC 偏移 32/64 位的 [31 ... 12] 位
|`+(*(uint32_t *) PC) [24 ... 5] = (((GP+G) & ~0xfff) - (PC & ~0xfff)) [31 ... 12]+`
|`+(*(uint32_t *) PC) [24 ... 5] = (hi20(GP+G) - (PC & ~0xfff)) [31 ... 12]+` footnote:foot_hi20[]

|76
|R_LARCH_GOT_PC_LO12
Expand All @@ -730,12 +732,12 @@ v2.00
|77
|R_LARCH_GOT64_PC_LO20
|GOT 表项相对 PC 偏移 64 位的 [51 ... 32] 位
|`+(*(uint32_t *) PC) [24 ... 5] = (GP+G - (PC & ~0xffffffff)) [51 ... 32]+`
|`+(*(uint32_t *) PC) [24 ... 5] = (hi32(GP+G) - (PC & ~0xffffffff)) [51 ... 32]+` footnote:foot_hi32[]

|78
|R_LARCH_GOT64_PC_HI12
|GOT 表项相对 PC 偏移 64 位的 [63 ... 52] 位
|`+(*(uint32_t *) PC) [21 ... 10] = (GP+G - (PC & ~0xffffffff)) [63 ... 52]+`
|`+(*(uint32_t *) PC) [21 ... 10] = (hi32(GP+G) - (PC & ~0xffffffff)) [63 ... 52]+` footnote:foot_hi32[]

|79
|R_LARCH_GOT_HI20
Expand Down Expand Up @@ -780,7 +782,7 @@ v2.00
|87
|R_LARCH_TLS_IE_PC_HI20
|TLS IE 符号 GOT 表项相对 PC 偏移 32/64 位的 [31 ... 12] 位
|`+(*(uint32_t *) PC) [24 ... 5] = (((GP+IE) & ~0xfff) - (PC & ~0xfff)) [31 ... 12]+`
|`+(*(uint32_t *) PC) [24 ... 5] = (hi20(GP+IE) - (PC & ~0xfff)) [31 ... 12]+` footnote:foot_hi20[]

|88
|R_LARCH_TLS_IE_PC_LO12
Expand All @@ -790,12 +792,12 @@ v2.00
|89
|R_LARCH_TLS_IE64_PC_LO20
|TLS IE 符号 GOT 表项相对 PC 偏移 64 位的 [51 ... 32] 位
|`+(*(uint32_t *) PC) [24 ... 5] = (GP+IE - (PC & ~0xffffffff)) [51 ... 32]+`
|`+(*(uint32_t *) PC) [24 ... 5] = (hi32(GP+IE) - (PC & ~0xffffffff)) [51 ... 32]+` footnote:foot_hi32[]

|90
|R_LARCH_TLS_IE64_PC_HI12
|TLS IE 符号 GOT 表项相对 PC 偏移 64 位的 [63 ... 52] 位
|`+(*(uint32_t *) PC) [21 ... 10] = (GP+IE - (PC & ~0xffffffff)) [63 ... 52]+`
|`+(*(uint32_t *) PC) [21 ... 10] = (hi32(GP+IE) - (PC & ~0xffffffff)) [63 ... 52]+` footnote:foot_hi32[]

|91
|R_LARCH_TLS_IE_HI20
Expand All @@ -820,7 +822,7 @@ v2.00
|95
|R_LARCH_TLS_LD_PC_HI20
|TLS LD 符号 GOT 表项相对 PC 偏移 32/64 位的 [31 ... 12] 位
|`+(*(uint32_t *) PC) [24 ... 5] = (((GP+GD) & ~0xfff) - (PC & ~0xfff)) [31 ... 12]+`
|`+(*(uint32_t *) PC) [24 ... 5] = (hi20(GP+GD) - (PC & ~0xfff)) [31 ... 12]+` footnote:foot_hi20[]

|96
|R_LARCH_TLS_LD_HI20
Expand All @@ -830,7 +832,7 @@ v2.00
|97
|R_LARCH_TLS_GD_PC_HI20
|TLS GD 符号 GOT 表项相对 PC 偏移 32/64 位的 [31 ... 12] 位
|`+(*(uint32_t *) PC) [24 ... 5] = (((GP+GD) & ~0xfff) - (PC & ~0xfff)) [31 ... 12]+`
|`+(*(uint32_t *) PC) [24 ... 5] = (hi20(GP+GD) - (PC & ~0xfff)) [31 ... 12]+` footnote:foot_hi20[]

|98
|R_LARCH_TLS_GD_HI20
Expand Down
27 changes: 16 additions & 11 deletions docs/LoongArch-ELF-ABI-EN.adoc
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -696,7 +696,9 @@ with check 28-bit signed overflow and 4-bit aligned
|71
|R_LARCH_PCALA_HI20
|[31 ... 12] bits of 32/64-bit PC-relative offset
|`+(*(uint32_t *) PC) [24 ... 5] = (((S+A) & ~0xfff) - (PC & ~0xfff)) [31 ... 12]+`
|`+(*(uint32_t *) PC) [24 ... 5] = (hi20(S+A) - (PC & ~0xfff)) [31 ... 12]+` footnote:foot_hi20[`hi20(x)` is defined as `(x + 0x800) & ~0xfff`.
The additional `+ 0x800` makes the result suitable for an addition with
`x & 0xfff` as a 12-bit signed integer.]

`+Note: The lower 12 bits are not included when calculating the PC-relative offset.+`

Expand All @@ -708,17 +710,20 @@ with check 28-bit signed overflow and 4-bit aligned
|73
|R_LARCH_PCALA64_LO20
|[51 ... 32] bits of 64-bit PC-relative offset
|`+(*(uint32_t *) PC) [24 ... 5] = (S+A - (PC & ~0xffffffff)) [51 ... 32]+`
|`+(*(uint32_t *) PC) [24 ... 5] = (hi32(S+A) - (PC & ~0xffffffff)) [51 ... 32]+` footnote:foot_hi32[`hi32(x)` is defined as
`x - ((x & 0x800) << 21)`. The additional `-((x & 0x800) << 21)` makes the
result suitable for addition with `x & 0xfff` as a 12-bit signed integer
extended to 32-bit and `hi20(x)`.]

|74
|R_LARCH_PCALA64_HI12
|[63 ... 52] bits of 64-bit PC-relative offset
|`+(*(uint32_t *) PC) [21 ... 10] = (S+A - (PC & ~0xffffffff)) [63 ... 52]+`
|`+(*(uint32_t *) PC) [21 ... 10] = (hi32(S+A) - (PC & ~0xffffffff)) [63 ... 52]+` footnote:foot_hi32[]

|75
|R_LARCH_GOT_PC_HI20
|[31 ... 12] bits of 32/64-bit PC-relative offset to GOT entry
|`+(*(uint32_t *) PC) [24 ... 5] = (((GP+G) & ~0xfff) - (PC & ~0xfff)) [31 ... 12]+`
|`+(*(uint32_t *) PC) [24 ... 5] = (hi20(GP+G) - (PC & ~0xfff)) [31 ... 12]+` footnote:foot_hi20[]

|76
|R_LARCH_GOT_PC_LO12
Expand All @@ -728,12 +733,12 @@ with check 28-bit signed overflow and 4-bit aligned
|77
|R_LARCH_GOT64_PC_LO20
|[51 ... 32] bits of 64-bit PC-relative offset to GOT entry
|`+(*(uint32_t *) PC) [24 ... 5] = (GP+G - (PC & ~0xffffffff)) [51 ... 32]+`
|`+(*(uint32_t *) PC) [24 ... 5] = (hi32(GP+G) - (PC & ~0xffffffff)) [51 ... 32]+` footnote:foot_hi32[]

|78
|R_LARCH_GOT64_PC_HI12
|[63 ... 52] bits of 64-bit PC-relative offset to GOT entry
|`+(*(uint32_t *) PC) [21 ... 10] = (GP+G - (PC & ~0xffffffff)) [63 ... 52]+`
|`+(*(uint32_t *) PC) [21 ... 10] = (hi32(GP+G) - (PC & ~0xffffffff)) [63 ... 52]+` footnote:foot_hi32[]

|79
|R_LARCH_GOT_HI20
Expand Down Expand Up @@ -778,7 +783,7 @@ with check 28-bit signed overflow and 4-bit aligned
|87
|R_LARCH_TLS_IE_PC_HI20
|[31 ... 12] bits of 32/64-bit PC-relative offset to TLS IE GOT entry
|`+(*(uint32_t *) PC) [24 ... 5] = (((GP+IE) & ~0xfff) - (PC & ~0xfff)) [31 ... 12]+`
|`+(*(uint32_t *) PC) [24 ... 5] = (hi20(GP+IE) - (PC & ~0xfff)) [31 ... 12]+` footnote:foot_hi20[]

|88
|R_LARCH_TLS_IE_PC_LO12
Expand All @@ -788,12 +793,12 @@ with check 28-bit signed overflow and 4-bit aligned
|89
|R_LARCH_TLS_IE64_PC_LO20
|[51 ... 32] bits of 64-bit PC-relative offset to TLS IE GOT entry
|`+(*(uint32_t *) PC) [24 ... 5] = (GP+IE - (PC & ~0xffffffff)) [51 ... 32]+`
|`+(*(uint32_t *) PC) [24 ... 5] = (hi32(GP+IE) - (PC & ~0xffffffff)) [51 ... 32]+` footnote:foot_hi32[]

|90
|R_LARCH_TLS_IE64_PC_HI12
|[63 ... 52] bits of 64-bit PC-relative offset to TLS IE GOT entry
|`+(*(uint32_t *) PC) [21 ... 10] = (GP+IE - (PC & ~0xffffffff)) [63 ... 52]+`
|`+(*(uint32_t *) PC) [21 ... 10] = (hi32(GP+IE) - (PC & ~0xffffffff)) [63 ... 52]+` footnote:foot_hi32[]

|91
|R_LARCH_TLS_IE_HI20
Expand All @@ -818,7 +823,7 @@ with check 28-bit signed overflow and 4-bit aligned
|95
|R_LARCH_TLS_LD_PC_HI20
|[31 ... 12] bits of 32/64-bit PC-relative offset to TLS LD GOT entry
|`+(*(uint32_t *) PC) [24 ... 5] = (((GP+GD) & ~0xfff) - (PC & ~0xfff)) [31 ... 12]+`
|`+(*(uint32_t *) PC) [24 ... 5] = hi20(GP+GD) - (PC & ~0xfff)) [31 ... 12]+` footnote:foot_hi20[]

|96
|R_LARCH_TLS_LD_HI20
Expand All @@ -828,7 +833,7 @@ with check 28-bit signed overflow and 4-bit aligned
|97
|R_LARCH_TLS_GD_PC_HI20
|[31 ... 12] bits of 32/64-bit PC-relative offset to TLS GD GOT entry
|`+(*(uint32_t *) PC) [24 ... 5] = (((GP+GD) & ~0xfff) - (PC & ~0xfff)) [31 ... 12]+`
|`+(*(uint32_t *) PC) [24 ... 5] = hi20(GP+GD) - (PC & ~0xfff)) [31 ... 12]+` footnote:foot_hi20[]

|98
|R_LARCH_TLS_GD_HI20
Expand Down